Wireless communication system, terminal device, wireless communication method and integrated circuit

ABSTRACT

Provided is a wireless communication system in which a first base station apparatus and a second base station apparatus perform communication with a terminal device, in which the first base station apparatus transmits radio resource configuration information including radio bearer configuration information of the first base station apparatus or the second base station apparatus, to the terminal device, in which the terminal device receives the radio resource configuration information, in which the terminal device executes a re-establishment procedure in a case where a random access failure with respect to the first base station apparatus is detected, and in which, in a case where a random access failure with respect to the second base station apparatus is detected, the terminal device transmits to the first base station apparatus a message indicating that the random access failure with respect to the second base station apparatus is detected and deletes the radio bearer configuration information for the second base station apparatus.

TECHNICAL FIELD

The present invention relates to a wireless communication system, a basestation apparatus, and a terminal device, and more particularly to awireless communication system, a terminal device, a wirelesscommunication method, and an integrated circuit, all of which relate todata control.

This application claims the benefit of Japanese Priority PatentApplication No. 2014-054945 filed on Mar. 18, 2014, the entire contentsof which are incorporated herein by reference.

BACKGROUND ART

In 3rd Generation Partnership Project (3GPP), a W-CDMA scheme has beenstandardized as a third generation cellular mobile communication system,and is in service. Furthermore, HSDPA in which communication speed isfurther increased has been standardized as well and is in service.

On the other hand, in 3GPP, standardization of Evolved UniversalTerrestrial Radio Access (which is hereinafter referred to as “EUTRA”)has been performed as well and has started to be in service. As adownlink communication scheme for EUTRA, an Orthogonal FrequencyDivision Multiplexing (OFDM) scheme, which is highly resistant tomulti-path interference and is suitable for high-speed transfer, isemployed. Furthermore, as an uplink communication scheme, a DiscreteFourier Transform (DFT)-spread OFDM scheme for Single Carrier-FrequencyDivision Multiple Access (SC-FDMA) that is capable of reducing a Peak toAverage Power Ratio (PAPR) for a transmission signal is employedconsidering the cost of and power consumption by a mobile stationapparatus.

Furthermore, in 3GPP Advanced-EUTRA that is a further advanced versionof EUTRA has been started to be studied as well. It is assumed that inAdvanced-EUTRA, a band up to a maximum bandwidth of 100 MHz is used ineach of the uplink and the downlink, and that communication is performedto the maximum at a transfer rate of 1 Gbps or more in the downlink andat a transfer rate of 500 Mbps or more in the uplink.

It is considered that in Advanced-EUTRA, multiple bands that arecompatible with EUTRA are aggregated in such a manner that the mobilestation apparatus for EUTRA can be accommodated as well, and thus amaximum band of 100 MHz is realized. Moreover, in Advanced-EUTRA, oneband of 20 MHz or less for EUTRA is referred to as a Component Carrier(CC). The component carrier is also referred to a cell. Furthermore, theaggregating of bands of 20 MHz or less is referred to as CarrierAggregation (CA) (NPL 1).

Furthermore, in Advanced-EUTRA, it is considered that the CarrierAggregation is performed within a frequency or between frequencies in aMacro Cell and a Small Cell within a range of the Macro Cell. Beingwithin the range of the Macro Cell includes frequencies being differentfrom each other. In NPL 2, it is proposed that in communication betweena base station apparatus and the mobile station apparatus at the time ofthe Carrier Aggregation in the Macro Cell and the Small Cell, controlinformation (Control-Plane Information) is transmitted in the Macro Celland user information (User-Plane Information) is transmitted in theSmall Cell. The Carrier Aggregation in the Macro Cell and the Small Cellthat is illustrated in NPL 2 is also referred to as Dual Connect (orDual Connectivity).

Moreover, it is also considered that, with the Dual Connect, informationon the same radio bearer (RB) is transmitted from the base stationapparatus in the Macro Cell and the base station apparatus in the Smallcell to the mobile station apparatus and the information on the sameradio bearer (RB) is transmitted from the mobile station apparatus tothe base station apparatus in the Macro Cell and the base stationapparatus in the Small Cell. Moreover, control in which the base stationapparatus and the mobile station apparatus transmit and receive theinformation on the same radio bearer through different base stationapparatuses is referred to as Bearer Split.

CITATION LIST Non Patent Literature

-   NPL 1: 3GPP TS (Technical Specification) 36.300, V11.7.0 (2013-09),    Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved    Universal Terrestrial Radio Access Network (E-UTRAN), Overall    description Stage 2-   NPL 2: 3GPP TR (Technical Report) 36.842, V1.0.0 (2013-11), Study on    Small Cell Enhancements for E-UTRA and E-UTRAN—Higher layer aspects    (release 12)

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

However, in the communication between the base station apparatus and themobile station apparatus as illustrated in NPL 2, in a case where theBearer Split is performed between the base station apparatus in theMacro Cell and the base station apparatus in the Small Cell, and themobile station apparatus, and where data transmission and reception areperformed, if control is not performed in which a suitable cell isselected and the data transmission and reception are performed, datathroughput is decreased.

Particularly, in a case where the Bearer Split is performed on uplinkdata from the mobile station apparatus to the base station apparatus inthe Macro Cell and the base station apparatus in the Small Cell, themobile station apparatus has to suitably select a cell in which totransmit data. Furthermore, even in a case where it is difficult for themobile station apparatus to communicate with one of the base stationapparatuses, the communication has to continue.

An object of the present invention, which was made in view of thissituation, is to provide a wireless communication system, and a mobilestation apparatus, a wireless communication method, and an integratedcircuit, in each of which it is possible that the mobile stationapparatus efficiently performs the data transmission processing at thetime of the Bearer Split for the Dual Connect.

Means for Solving the Problems

(1) In order to accomplish the object described above, the presentinvention is contrived to provide the following means. That is,according to an aspect of the present invention, there is provided awireless communication system in which a first base station apparatusand a second base station apparatus perform communication with aterminal device, in which the first base station apparatus transmitsradio resource configuration information including radio bearerconfiguration information of the first base station apparatus and/or thesecond base station apparatus, to the terminal device, and in which, theterminal device transmits to the first base station apparatus a messageindicating that a random access failure with respect to the second basestation apparatus is detected, in a case where the random access failurewith respect to the second base station apparatus is detected, andsuspends a radio bearer for the second base station apparatus and aradio bearer resulting from Bearer Split for the second base stationapparatus, which are configured with the radio bearer configurationinformation.

(2) Furthermore, according to another aspect of the present invention,there is provided a terminal device that performs communication with afirst base station apparatus and a second base station apparatus througha cell in a master cell group that belongs to the first base stationapparatus and a cell in a secondary cell group that belongs to thesecond base station apparatus, the terminal device including: an RRClayer that suspends a Radio bearer that corresponds to the secondarycell group and a radio bearer resulting from Bearer Split thatcorresponds to the secondary cell group, in a case where a random accessproblem is notified by a MAC layer that corresponds to the secondarycell group, and performs MAC reset of the MAC layer.

(3) Furthermore, in the terminal device according to the aspect of thepresent invention, the RRC layer may be constituted in such a manner asto create a message indicating that the random access failure withrespect to the secondary cell group.

(4) Furthermore, according to still another aspect of the presentinvention, there is provided a wireless communication method that isapplied to a wireless communication system in which a first base stationapparatus and a second base station apparatus perform communication witha terminal device, the wireless communication method including: a stepof causing the first base station apparatus to transmit radio resourceconfiguration information including radio bearer configurationinformation of the first base station apparatus or the second basestation apparatus, to the terminal device: a step of causing theterminal device to receive the radio resource configuration information;a step of causing the terminal device to transmit to the first basestation apparatus a message indicating that a random access failure withrespect to the second base station apparatus is detected, in a casewhere the random access failure with respect to the second base stationapparatus is detected; and a step of causing the terminal device tosuspend a radio bearer for the second base station apparatus and a radiobearer resulting from Bearer Split for the second base stationapparatus, which are configured with the radio bearer configurationinformation.

(5) Furthermore, according to still another aspect of the presentinvention, there is provided an integrated circuit that is applied to aterminal device that performs communication with a first base stationapparatus and a second base station apparatus through a cell in a mastercell group that belongs to the first base station apparatus and a cellin a secondary cell group that belongs to the second base stationapparatus, the integrated circuit including: means for causing an RRClayer to suspend a Radio bearer that corresponds to the secondary cellgroup and a radio bearer resulting from Bearer Split that corresponds tothe secondary cell group, in a case where a random access problem isnotified by a MAC layer that corresponds to the secondary cell group;and means for causing the RRC layer to perform MAC reset of the MAClayer.

Effects of the Invention

According to the present invention, it is possible that efficient datatransmission is performed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating one example of a constitution of amobile station apparatus according to an embodiment of the presentinvention.

FIG. 2 is a diagram illustrating one example of a constitution of a basestation apparatus according to the embodiment of the present invention.

FIG. 3 is a diagram illustrating one example of the constitution of thebase station apparatus according to the embodiment of the presentinvention.

FIG. 4 is a diagram illustrating one example of a constitution of acommunication protocol for the mobile station apparatus according to theembodiment of the present invention.

FIG. 5 is a diagram illustrating one example of the constitution of thecommunication protocol for the mobile station apparatus according to theembodiment of the present invention.

FIG. 6 is a diagram illustrating one example of a constitution of aPhysical Channel in EUTRA.

FIG. 7 is a diagram illustrating one example of a constitution of adownlink channel in EUTRA.

FIG. 8 is a diagram illustrating one example of a constitution of anuplink channel in EUTRA.

FIG. 9 is a diagram illustrating one example of a constitution of acommunication protocol relating to control information on the basestation apparatus and the mobile station apparatus.

FIG. 10 is a diagram illustrating one example of a constitution of acommunication protocol relating to user information of the base stationapparatus and the mobile station apparatus.

FIG. 11 is a diagram for describing one example of Dual Connect.

FIG. 12 is a diagram for describing one example of the Dual Connect.

FIG. 13 is a diagram for describing one example of the Dual Connect.

MODE FOR CARRYING OUT THE INVENTION

An OFDM scheme is employed as for downlink for EUTRA. Furthermore, asingle carrier communication scheme that is a DFT-spread OFDM scheme isemployed as uplink for EUTRA.

FIG. 6 is a diagram illustrating a constitution of a Physical Channelfor EUTRA. A downlink physical channel is constituted from a PhysicalDownlink Shared Channel (PDSCH), a Physical Downlink Control Channel(PDCCH), and a Physical Broadcast Channel (PBCH). In addition to these,there is a physical signal that is a downlink reference signal (NPL 1).

An uplink physical channel is constituted from a Physical Random AccessChannel (PRACH), Physical Uplink Shared Channel (PUSCH), and a PhysicalUplink Control Channel (PUCCH). In addition to these, there is aphysical signal that is an uplink reference signal (NPL 1).

FIG. 7 is a diagram illustrating a constitution of a downlink channelfor EUTRA. Each downlink channel that is illustrated in FIG. 7 isconstituted from a logical channel, a transport channel, and a physicalchannel. The logical channel defines a type of data transmission servicethat is transmitted and received with a Medium Access Control (MAC)layer. The transport channel defines what attribute data that istransmitted with a wireless interface has and how the data istransmitted. The physical channel is a physical channel on which totransport data which is transferred on the transport channel to aPhysical Layer.

Downlink logical channels include a Broadcast Control Channel (BCCH), aPaging Control Channel (PCCH), a Common Control Channel (CCCH), aDedicated Control Channel (DCCH), and a Dedicated Traffic Channel(DTCH).

Downlink transport channels include a Broadcast Channel (BCH), a PagingChannel (PCH), and a Downlink Shared Channel (DL-SCH).

Downlink physical channels includes a Physical Broadcast Channel (PBCH),a Physical Downlink Control Channel (PDCCH), and a Physical DownlinkShared Channel (PDSCH). These channels are transmitted and receivedbetween the base station apparatus and the mobile station apparatus.

Next, the logical channel is described. The broadcast control channel(BCCH) is a downlink channel that is used for broadcasting systemcontrol information. The paging control channel (PCCH) is a downlinkchannel that is used for transmitting paging information, and is usedwhen a network does not know a cell location of the mobile stationapparatus. The Common Control Channel (CCCH) is a channel that is usedfor transmitting control information between the mobile stationapparatus and the network, and is used by the mobile station apparatusthat does not have a Radio Resource Control (RRC) connection to thenetwork.

The Dedicated Common Control Channel (DCCH) is a point-to-pointbidirectional channel, and is a channel that is used for transmittingthe individual control information between the mobile station apparatusand the network. The Dedicated Common control channel (DCCH) is used bythe mobile station apparatus that has the RRC connection. The DedicatedTraffic Channel (DTCH) is a point-to-point bidirectional channel, is achannel dedicated for one mobile station apparatus, and is used for thetransfer of the user information (the unicast data).

Next, the transport channel is described. The Broadcast Channel (BCH) isbroadcast to all cells in a transmission format that is fixed and is inadvance defined. On the Downlink Shared Channel (DL-SCH), a HybridAutomatic Repeat Request (HARQ), dynamic adaptive radio link control,Discontinuous Reception (DRX) are supported, and the Downlink SharedChannel needs to be broadcast to all cells.

On the Paging Channel (PCH), the DRX is supported, and the PagingChannel needs to be broadcast to all cells. Furthermore, the PagingChannel (PCH) is mapped to a physical resource that is used dynamicallyfor the transport channel or other control channels, that is, to thePhysical Downlink Shared Channel (PDSCH).

Next, the physical channel is described. The Physical Broadcast Channel(PBCH) maps the Broadcast Channel (BCH) with a periodicity of 40milliseconds. The Physical Downlink Control Channel (PDCCH) is a channelthat is used for notifying the mobile station apparatus of resourceallocation of the Downlink Shared Channel (PDSCH), Hybrid AutomaticRepeat Request (HARQ) information for downlink data, and an uplinktransmission approval (uplink grant) that is resource allocation of thePhysical Uplink Shared Channel (PUSCH). The Physical Downlink SharedChannel (PDSCH) is a channel that is used for transmitting the downlinkdata or the paging information.

Next, the channel mapping is described. As illustrated in FIG. 7, indownlink, mapping between the transport channel and the physical channelis performed as follows. The Broadcast Channel (BCH) is mapped to thePhysical Broadcast Channel (PBCH). The Paging Channel (PCH) and theDownlink Shared Channel (DL-SCH) are mapped to the Physical DownlinkShared Channel (PDSCH). The Physical Downlink Control Channel (PDCCH) isused in a stand-alone manner as a physical channel.

Furthermore, in the downlink, mapping between the logical channel andthe transport channel is performed as follows. The Paging ControlChannel (PCCH) is mapped to the Paging Channel (PCH). The BroadcastControl Channel (BCCH) is mapped the Broadcast Channel (BCH) and theDownlink Shared Channel (DL-SCH). The Common Control Channel (CCCH), theDedicated Control Channel (DCCH), and the Dedicated Traffic Channel(DTCH) are mapped to the Downlink Shared Channel (DL-SCH).

FIG. 8 is a diagram of a constitution of an uplink channel for EUTRA.Each uplink channel that is illustrated in FIG. 8 is constituted from alogical channel, a transport channel, and a physical channel. Thedefinition by each channel is the same as in the downlink channel.

Uplink logical channels include a Common Control Channel (CCCH), aDedicated Control Channel (DCCH), and a Dedicated Traffic Channel(DTCH).

Uplink transport channels include Uplink Shared Channel (UL-SCH) and aRandom Access Channel (RACH).

Uplink physical channels include a Physical Uplink Control Channel(PUCCH), a Physical Uplink Shared Channel (PUSCH), and a Physical RandomAccess Channel (PRACH). These channels are transmitted and receivedbetween the base station apparatus and the mobile station apparatus.Moreover, the Physical Random Access Channel (PRACH) is used fortransmitting a random access preamble for acquiring transmission timinginformation from the base station apparatus to the base stationapparatus. The transmission of the random access preamble transmissionis performed while a random access procedure is being executed.

Next, the logical channel is described. The Common Control Channel(CCCH) is a channel that is used for transmitting the controlinformation between the mobile station apparatus and the network, and isused by the mobile station apparatus that does not establish the RadioResource Control (RRC) connection to the network.

The Dedicated Common Control Channel (DCCH) is a point-to-pointbidirectional channel, and is a channel that is used for transmittingthe individual control information between the mobile station apparatusand the network. The Dedicated Common control channel (DCCH) is used bythe mobile station apparatus that has the RRC connection. The DedicatedTraffic Channel (DTCH) is a point-to-point bidirectional channel, is achannel dedicated for one mobile station apparatus, and is used for thetransfer of the user information (the unicast data).

Next, the transport channel is described. On the Uplink Shared Channel(UL-SCH), a Hybrid Automatic Repeat Request (HARQ), dynamic adaptiveradio link control, Discontinuous transmission (DTX) are supported. Onthe Random Access Channel (RACH), limited control information istransmitted.

Next, the physical channel is described. The Physical Uplink ControlChannel (PUCCH) is a channel that is used for notifying the base stationapparatus of response information (ACK/NACK) in response to the downlinkdata, downlink wireless channel quality information, and transmissionrequest (Scheduling Request (SR)) for uplink data. The Physical UplinkShared Channel (PUSCH) is a channel that is used for transmitting theuplink data. The Physical Random Access Channel is a channel that isused for transmitting the random access preamble.

Next, the channel mapping is described. In uplink, the mapping betweenthe transport channel and the physical channel as illustrated in FIG. 8is performed. The Uplink Shared Channel (UL-SCH) is mapped to thePhysical Uplink Shared Channel (PUSCH). The Random Access Channel (RACH)is mapped to the Physical Random Access Channel (PRACH). The PhysicalUplink Control Channel (PUCCH) is a physical channel for which there isno transport channel to be mapped.

Furthermore, in the uplink, the mapping between the logical channel andthe transport channel is performed as follows. The Common ControlChannel (CCCH), the Dedicated Control Channel (DCCH), and the DedicatedTraffic Channel (DTCH) are mapped to the Uplink Shared Channel (UL-SCH).

FIG. 9 is a protocol stack that handles control data of each of themobile station apparatus and the base station apparatus for EUTRA. FIG.10 is a protocol stack that handles user data of each of the mobilestation apparatus and the base station apparatus for EUTRA. Adescription is provided below referring to FIGS. 9 and 10.

The Physical Layer (PHY layer) provides a transfer size to a higherlayer using the Physical Channel. The PHY layer is connected to ahigher-level Medium Access Control layer (MAC layer) with the transportchannel. Through the transport channel, data moves between layers, theMAC layer and the PHY layer. Between the PHY layers of the terminaldevice and the base station apparatus, data transmission and receptionare performed through the Physical Channel.

The MAC layer performs mapping of various Logical Channels on varioustransport channels. The MAC layer is connected to a higher-level RadioLink Control layer (RLC layer) with the logical channel. The logicalchannel is broadly divided by a type of information that is transferred,and is divided into a control channel on which the control informationis transferred and a traffic channel on which the user information istransferred. In order to perform the discontinuous reception andtransmission (DRX/DTX), the MAC layer has a function of performingcontrol of the PHY layer, a function of executing the random accessprocedure, a function of notifying transmit power information (a powerheadroom report), a function of performing HARQ control, and the like.

The RLC layer performs segmentation and concatenation of data that isreceived from the higher layer, and adjusts a data size in such a mannerthat a lower layer can suitably perform data transmission. The RLC layerperforms the concatenation of the data that is received from the lowerlayer, and transfers the resulting data to the higher layer.Furthermore, the RLC layer has a function (data retransmission control)for guaranteeing Quality of Service (QoS) that is requested by eachpiece of data.

Sizes of the RLC layer are three modes, that is, a Transparent Mode(TM), an Unacknowledged Mode (UM), and an Acknowledged Mode (AM). TheTransparent Mode (TM) is a size for transferring without any change thedata that is received from the higher layer. The Unacknowledged Mode(UM) is a size for attaching a sequence number in the RLC layer on thetransmission side RLC layer, checking for order in the RLC layer on thereception side, destroying redundant data, and so forth. TheAcknowledged Mode (AM) is a size for providing retransmission control.

In order to efficiently transfer in a wireless section an IP packet thatis the user data, a Packet Data Convergence Protocol layer (PDCP layer)has a header compression function of performing compression of thecontrol information. Furthermore, the PDCP layer has a data encryptionfunction as well.

A Radio Resource Control layer (RRC layer) defines only the controlinformation. The RRC layer performs configuration or reconfiguration ofa radio bearer (RB), and performs control of the logical channel, thetransport channel, and the Physical Channel. The RB is divided into asignaling radio bearer (SRB) and a data radio bearer (DRB). The SRB isused as a path along which an RRC message that is the controlinformation is transmitted. The DRB is used as a path along which theuser data is transmitted. Configuration of each RB is performed betweenthe RRC layers of the base station apparatus and the mobile stationapparatus.

Moreover, the PHY layer corresponds to the Physical Layer that is thefirst layer in a hierarchical structure of the Open SystemsInterconnection (OSI) model that is generally known, the MAC layer, andthe RLC layer and the PDCP layer correspond to a data link layer that isthe second layer of the OSI model, and the RRC layer corresponds to anetwork layer that is the third layer of the OSI model.

The random access procedure will be described below. The random accessprocedures include two random access procedures (NPL 1). One is aContention based Random Access Procedure and the other is aNon-contention based Random Access procedure.

The Contention based Random Access procedure is a random accessprocedure in which there is a likelihood that contention will take placebetween mobile station apparatuses, and is performed at the SchedulingRequest, such as during the time from a state where a connection(communication with) to the base station apparatus is not made to wheninitial access takes place, or in a case where the connection to thebase station apparatus is made but uplink data transmission takes placeto the mobile station apparatus in a state where uplink synchronizationis no longer maintained.

The Non-contention based Random Access procedure is a random accessprocedure in which the contention does not take place between the mobilestation apparatuses. In order to quickly achieve the uplinksynchronization between the mobile station apparatus and the basestation apparatus in a case where a connection is made between the basestation apparatus and the mobile station apparatus but the uplinksynchronization is no longer maintained, in a special case such as acase where a handover or a transmission timing for the mobile stationapparatus is not enabled, the mobile station apparatus starts the randomaccess procedure when is instructed by the base station apparatus to doso. An instruction to execute the Non-contention based Random Accessprocedure is provided using a Radio Resource Control (RRC) (Layer 3)layer message and control data on the Physical Downlink Control Channel(PDCCH).

The contention based Random Access procedure is briefly described.First, the mobile station apparatus 1-1 selects the random accesspreamble using random access procedure configuration information, andtransmits the random access preamble to a base station apparatus 3-1(message 1: (1) Step S1). Then, the base station apparatus 3-1 thatreceives the random access preamble transmits a response (a randomaccess response) to the random access preamble to a mobile stationapparatus 1-1 (message 2: (2) in Step S2). The mobile station apparatus1-1 transmits a higher layer (Layer 2/Layer 3) message, based onscheduling information that is included in the random access response(message 3: (3) in Step S3). The base station apparatus 3-1 transmits acontention resolution message to the mobile station apparatus 1-1 thatreceives the higher layer message of (3) (message 4: (4) in Step S4).Moreover, the Contention based Random Access is also referred to asrandom preamble transmission.

The Non-contention based Random Access procedure is briefly described.First, the base station apparatus 3-1 notifies the mobile stationapparatus 1-1 of a preamble number (or a sequence number) and a randomaccess channel number to be used (message 0: (1)′ in Step S11). Themobile station apparatus 1-1 transmits the random access preamble of thedesignated preamble number to a designated Random Access Channel (RACH)(message 1: (2)′ in Step S12). Then, the base station apparatus 3-1 thatreceives the random access preamble transmits the response (the randomaccess response) to the random access preamble to the mobile stationapparatus 1-1 (message 2: (3)′ in Step S13). However, in a case where avalue of the notified preamble number is 0, the Contention based RandomAccess procedure is executed. Moreover, the Non-contention based RandomAccess procedure is also referred to as dedicated preamble transmission.

Moreover, the mobile station apparatus 1-1 acquires the random accessprocedure configuration information from the base station apparatus 3-1.Furthermore, the mobile station apparatus 1-1 acquires physical randomaccess configuration information from the base station apparatus 3-1.Pieces of random access procedure configuration information includeinformation on the number of random preambles, information relating torandom access response reception, information relating to random accesspreamble transmission, information relating message 3 transmission, andinformation relating to contention resolution message reception, and thelike. Furthermore, pieces of physical random access channelconfiguration information include information on allocation of thePhysical Random Access Channel, information on generation of the randomaccess preamble, and the like.

The Scheduling Request (SR) will be described below. The Physical UplinkControl Channel (PUCCH) is used for transmission of a response (anACK/NACK of) to the downlink data that is transmitted on the PhysicalDownlink Shared Channel (PUSCH), wireless channel quality information (aChannel Quality Indicator (CQI)) in the downlink, and the transmissionrequest (Scheduling Request (SR)) for the uplink data. In a case wherethe mobile station apparatus 1-1 makes the transmission request for theuplink data, the mobile station apparatus 1-1 transmits the SchedulingRequest to the base station apparatus 3-1 using the Physical UplinkControl Channel (PUCCH) that is allocated by the base station apparatus3-1.

After the transmission of the Scheduling Request, in a case where thebase station apparatus 3-1 allocates the Physical Uplink Shared Channel(PUSCH), the mobile station apparatus 1-1 transmits a Buffer StatusReport (BSR) indicating a buffer status information of data that istransmitted, on the allocated Physical Uplink Shared Channel (PUSCH), bythe mobile station apparatus 1-1. Moreover, the base station apparatus3-1 performs uplink data scheduling on the mobile station apparatus 1-1based on the Buffer Status Report.

After the transmission of the Scheduling Request, in a case where thebase station apparatus 3-1 does not allocate the Physical Uplink SharedChannel (PUSCH), the mobile station apparatus 1-1 again transmits theScheduling Request. Although the retransmission of the SchedulingRequest is iterated, in the case where the base station apparatus 3-1does not allocate the Physical Uplink Shared Channel (PUSCH), the mobilestation apparatus 1-1 releases the Physical Uplink Control Channel(PUCCH) that is allocated and the uplink reference signal, and executesthe random access procedure that is intended for the Scheduling Request.Moreover, in the Scheduling Request using the random access procedure,with transmission of message 3, the mobile station apparatus 1-1transmits the Buffer Status Report.

A function of the MAC layer of the mobile station apparatus will bedescribed in more detail below. The MAC layer has a function of mappingeach Logical Channel to the transport channel. The procedure describedabove is also referred to as a Logical Channel Prioritization (LCP). Ina basic LCP procedure, transmission priority of the transmission data isdetermined considering a priority level of each logical channel and atransmission bit rate (Prioritized Bit Rate (PBR)) that has to betransmitted within a fixed period, which corresponds to QoS of the radiobearer, and mapping to the transport channel is performed starting fromdata with the highest priority at the point in time when the uplinkgrant is received. When making a connection to the base stationapparatus, the MAC layer acquires pieces of information, such as alogical channel number of each RB, the priority level of the LogicalChannel, and the PBR, from the RRC layer.

Furthermore, the MAC layer has a function of notifying an amount of datain a transmission buffer that corresponds to each logical channel. Thisfunction is referred to as the Buffer Status Report (BSR). With the BSR,each logical channel is allocated to a Logical Channel Group (LCG), andan amount of transmission buffer for each LCG is notified, as a messageof the MAC layer, to the base station apparatus.

As conditions for triggering the BSR, there are several conditions. Forexample, in a case where data available for transmission occurs andwhere the data has a higher priority level than data that is present inthe transmission buffer, the condition for triggering the BSR issatisfied. Furthermore, in a case where one periodic timer expires, thecondition for triggering the BSR is satisfied. Moreover, BSRs include aShort BSR in which a buffer status of one Logical Channel Group isreported, and a Long BSR in which a buffer status of multiple LogicalChannel Groups is reported.

Moreover, in a case where the condition for triggering the BSR issatisfied, if a radio resource (the Physical Uplink Shared Channel(PUSCH)) for notifying the BSR is not allocated, the MAC layer instructsthe PHY layer to transmit the Scheduling Request (SR). Because the radioresource is allocated, the MAC layer transmits the BSR. In a case wherethe PHY layer is instructed by the MAC layer to transmit the SchedulingRequest, the PHY layer transmits the Scheduling Request using thePhysical Uplink Control Channel (PUCCH). Moreover, in a case where thePhysical Uplink Control Channel (PUCCH) for the transmission of theScheduling Request is not allocated (is not enabled), the MAC layerinstructs the PHY layer to make the Scheduling Request that uses thePhysical Random Access Channel (PRACH).

Furthermore, the MAC layer has a function of notifying the transmitpower information of the mobile station apparatus 1-1. This function isreferred to as a Power Headroom Report (PHR). As conditions fortriggering the PHR, there are several conditions. For example, in a casewhere downlink wireless channel quality is compared with the channelquality that is previously measured, and where a change of a fixed valueor more takes place, the condition for triggering the PHR is satisfied.Furthermore, in a case where one periodic timer expires, the conditionfor triggering the PHR is satisfied.

In 3GPP, a study of Advanced-EUTRA that is a further advanced version ofEUTRA has been conducted as well. It is assumed that in Advanced-EUTRA,a band up to a maximum bandwidth of 100 MHz is used in each of theuplink and the downlink, and that transmission is performed to themaximum at a transfer rate of 1 Gbps or more in the downlink and at atransfer rate of 500 Mbps or more in the uplink.

It is considered that in Advanced-EUTRA, multiple bands of 20 MHz orless for EUTRA are aggregated in such a manner that the mobile stationapparatus for EUTRA can be accommodated as well, and thus a band of 100MHz is realized at the maximum. Moreover, in Advanced-EUTRA, one band of20 MHz or less for EUTRA is referred to as a Component Carrier (CC).Furthermore, a combination of one downlink component carrier and oneuplink component carrier constitutes one cell. Moreover, only onedownlink component carrier can constitute one cell as well.

The base station apparatus that is allocated multiple cells inaccordance with communication capability of and a communicationcondition in the mobile station apparatus is set in such a manner as toperform communication with the mobile station apparatus through theallocated multiple cells. Moreover, the multiple cells that areallocated to the mobile station apparatus are categorized into one cell,that is, a Primary Cell (PCell) and cells other than the one cell, thatis, Secondary Cells (SCells). A special function, such as the allocationof the Physical Uplink Control Channel (PUCCH), is configured for thePrimary Cell.

Furthermore, in order to decrease power consumption by the mobilestation apparatus, the mobile station apparatus is instructed by thebase station apparatus to activate (or to perform activation on) theSecondary Cell immediately after the allocation without performingdownlink reception processing (or without complying with radio resourceallocation information that is indicated with the Physical DownlinkControl Channel (PDCCH)), and then is set in such a manner as to startthe downlink reception processing on the Secondary Cell that the mobilestation apparatus is instructed to activate (or to comply with the radioresource allocation information that is indicated with the PhysicalDownlink Control Channel (PDCCH)).

Furthermore, the mobile station apparatus is instructed by the basestation apparatus to deactivate (or to perform deactivation on) theSecondary Cell that is activated and then is set in such a manner as tostop the downlink reception processing on the Secondary Cell that themobile station apparatus is instructed to deactivate (or not to complywith the radio resource allocation information that is indicated withthe Physical Downlink Control Channel (PDCCH)). Moreover, the SecondaryCell that is activated according to the instruction from the basestation apparatus and on which the downlink reception processing isperformed is referred to as an activated cell, and the Secondary Cellimmediately after being allocated by the base station apparatus to themobile station apparatus and the Secondary Cell that is deactivatedaccording to the base station apparatus and the downlink receptionprocessing on which is stopped are referred to as deactivated cells.Furthermore, the Primary Cell is at all times an activated cell.

Moreover, in a case of performing the Carrier Aggregation, the MAC layerof the mobile station apparatus has a function of performing the controlof the PHY layer to activate or deactivate a cell and a function ofperforming the control of the PHY layer to manage an uplink transmissiontiming.

Furthermore, it is also considered that the mobile station apparatus, asillustrated in FIG. 11, performs Dual Connect to two base stationapparatuses, and thus makes connections to both of the two base stationapparatuses at the same time. In the Dual Connect, it is assumed that,when a connection between the base station apparatus in a Macro Cell andthe base station apparatus in a Small Cell is made using a low-speedbackbone line (which is also referred to as backhaul) that causes adelay, not a high-speed backbone that is regarded as causing no delay,such as optical fiber, the mobile station apparatus makes connections tothe base station apparatus in the Macro Cell and the base stationapparatus in the Small Cell, and thus the mobile station apparatus andboth of the base station apparatuses perform the data transmission andreception through the multiple cells (NPL 2).

As in the Carrier Aggregation, in the Dual Connect, it is desirable thatthe communication is performed between the mobile station apparatus andthe base station apparatus with the Macro Cell as the Primary Cell(PCell) and the Small Cell as the Secondary Cell (SCell), and the DualConnect may be configured in such a manner that the Dual Connect has norelationship with a type of cell (the Macro Cell or the Small Cell) ofthe base station apparatus. Furthermore, in the Dual Connect, it isassumed that the transmission and reception of the control data (thecontrol information) is performed between the base station apparatus inthe Macro Cell and the mobile station apparatus, and that thetransmission and reception of the user data (the user information) isperformed between the base station apparatus in the Small Cell and themobile station apparatus.

Additionally, it is also considered that in addition to categorizations,that is, the control data and the user data, based on a type of data(for example, the QoS or the logical channel), the base stationapparatus that performs the data transmission and reception is changed.For example, it is considered that data on the same data radio bearer istransmitted from the base station apparatus that is different from thebase station apparatus in the Macro Cell and the base station apparatusin the Small Cell to the mobile station apparatus, and that the data onthe same data radio bearer is transmitted from the mobile stationapparatus to the base station apparatus in the Macro Cell and the basestation apparatus in the Small Cell.

In the Dual Connect as illustrated in FIG. 12, at least transmission andreception of the control information (control-plane information) of themobile station apparatus 1-1 is performed between the base stationapparatus 3-1 in the Macro Cell and a Mobility Management Entity (MME).At least transmission and reception of the user information (user-planeinformation) of the mobile station apparatus 1-1 is performed between abase station apparatus 3-2 in the Small Cell and a gateway (GW).Transmission and reception of the control information for controllingthe mobile station apparatus 1-1 is performed between the base stationapparatus 3-1 in the Macro Cell and the base station apparatus 3-2 inthe Small Cell.

At least the transmission and reception of the control information areperformed between the base station apparatus 3-1 in the Macro Cell andthe mobile station apparatus 1-1. The transmission and reception of theuser information are performed between the base station apparatus 3-2 inthe Small Cell and the mobile station apparatus 1-1. Moreover, thetransmission and reception of the user information are performed betweenthe base station apparatus 3-1 in the Macro Cell and the mobile stationapparatus 1-1.

Furthermore, in the Dual Connect as illustrated in FIG. 13, at least thetransmission and reception of the control information (control-planeinformation) of the mobile station apparatus 1-1 is performed betweenthe base station apparatus 3-1 in the Macro Cell and the MobilityManagement Entity (MME). At least the transmission and reception of theuser information (user-plane information) of the mobile stationapparatus 1-1 are performed between the base station apparatus 3-1 inthe Macro Cell and the gateway (GW).

The base station apparatus 3-1 in the Macro Cell transfers to the userinformation that is received from the GW, to the base station apparatus3-2 in the Small Cell. Furthermore, the base station apparatus 3-2 inthe Small Cell transfers the user information that is received from themobile station apparatus 1-1, to the base station apparatus 3-1.Furthermore, the transmission and reception of the control informationfor controlling the mobile station apparatus 1-1 is performed betweenthe base station apparatus 3-1 in the Macro Cell and the base stationapparatus 3-2 in the Small Cell.

The transmission and reception of the control information or the userinformation are performed between the base station apparatus 3-1 in theMacro Cell and the mobile station apparatus 1-1. The transmission andreception of the user information are performed between the base stationapparatus 3-2 in the Small Cell and the mobile station apparatus 1-1.Moreover, in the case of a constitution in FIG. 13, Bearer Split isperformed in which the mobile station apparatus and both of the basestation apparatuses transmits and receives information on the same radiobearer (RB) through both cells, that is, the Macro Cell and the SmallCell.

Moreover, a cell group that includes the Macro Cell which is provided bythe base station apparatus 3-1 is referred to as a master cell group(MCG), and a cell group that is constituted from one or more Small Cellswhich are provided by the base station apparatus 3-2 is referred to as asecondary cell group (SCG).

Moreover, in a case where one or both of a timing for reception in themobile station apparatus for every downlink component carrier, whichresults from an arrangement relationship between the base stationapparatuses and a timing for transmission to the base station apparatusfor every uplink component carrier differ from one cell to another,cells that are the same in terms of uplink transmission timing aregrouped and the communication is performed. A group of cells that arethe same in terms of transmission timing is referred to as atransmission timing group (Timing Advance Group). The MAC layer of themobile station apparatus has a function of controlling the PHY layer aswell in order to manage the transmission timing group.

EMBODIMENTS Constitution Description

FIG. 1 is a diagram illustrating a constitution of a mobile stationapparatus according to an embodiment of the present invention. Mobilestation apparatuses 1-1 to 1-3 each are constituted from an uplink dataprocessing unit 101, an uplink control unit 103-1, an uplink controlunit 103-2, a transmission data storage unit 105-1, a transmission datastorage unit 105-2, a transmission HARQ processing unit 107-1, atransmission HARQ processing unit 107-2, a transmission processing unit109-1, a transmission processing unit 109-2, a radio unit 111-1, a radiounit 111-2, a reception processing unit 113-1, a reception processingunit 113-2, a reception HARQ processing unit 115-1, a reception HARQprocessing unit 115-2, a MAC information extraction unit 117-1, a MACinformation extraction unit 117-2, a downlink control unit 119-1, adownlink control unit 119-2, a downlink data processing unit 121-1, adownlink data processing unit 121-2, a PHY control unit 123-1, a PHYcontrol unit 123-2, a MAC control unit 125-1, a MAC control unit 125-2,and a RRC control unit 127.

Moreover, the uplink control unit 103-1, the transmission data storageunit 105-1, the transmission HARQ processing unit 107-1, thetransmission processing unit 109-1, the radio unit 111-1, the PHYcontrol unit 123-1, and the MAC control unit 125-1 perform antransmission operation on the base station apparatus 3-1 (the MacroCell), and the uplink control unit 103-2, the transmission data storageunit 105-2, the transmission HARQ processing unit 107-2, thetransmission processing unit 109-2, the radio unit 111-2, the PHYcontrol unit 123-2, and the MAC control unit 125-2 performs atransmission operation on the base station apparatus 3-2 (the SmallCell).

The downlink control unit 119-1, the MAC information extraction unit117-1, the reception HARQ processing unit 115-1, the receptionprocessing unit 113-1, the radio unit 111-1, the PHY control unit 123-1,and the MAC control unit 125-1 perform the reception operation on thebase station apparatus 3-1, and the downlink control unit 119-2, the MACinformation extraction unit 117-2, the reception HARQ processing unit115-2, the reception processing unit 113-2, the radio unit 111-2, thePHY control unit 123-2, and the MAC control unit 125-2 perform thereception operation of the base station apparatus 3-2.

The user data from the higher layer and the RRC control unit 127 fromthe user data are input into the uplink data processing unit 101. Theuplink data processing unit 101 has a function of the PDCP layer. Theuplink data processing unit 101 performs processing operations, such ashead compression of or data encryption of an IP packet of the user data,data segmentation and concatenation, and adjusts a data size. The uplinkdata processing unit 101 outputs data on which the processing isperformed, to the uplink control unit 103-1 or the uplink control unit103-2. In a case where the uplink data processing unit 101 is instructedby the RRC control unit 127 to destroy data, the uplink data processingunit 101 destroys data that is being processed.

Moreover, according to an instruction from the base station apparatus3-1, the uplink data processing unit 101 may be set to output data tothe uplink control unit 103-1 or the uplink control unit 103-2.Furthermore, the uplink data processing unit 101 may be set to outputthe data to the uplink control unit 103-1 or the uplink control unit103-2, taking into consideration an amount of data that is accumulatedin the transmission data storage unit 105-1 and the transmission datastorage unit 105-2, a quality state of a wireless channel, and the like.

The uplink control unit 103-1 has a function of the RLC layer. Theuplink control unit 103-1 performs processing, such as the datasegmentation and concatenation, on the data that is input from theuplink data processing unit 101, and adjusts the data size. Furthermore,the uplink control unit 103-1 performs retransmission on specific data.The uplink control unit 103-1 outputs the data on which the processingis performed, to the transmission data storage unit 105-1.

The uplink control unit 103-1 counts the number of times that the dataon which retransmission control is performed is retransmitted. In a casewhere the number of times of retransmission reaches the maximum numberof times of RLC transmission that is acquired from the RRC control unit127, the uplink control unit 103-1 notifies the RRC control unit 127 ofan RLC failure.

In a case where the uplink control unit 103-1 is instructed by the RRCcontrol unit 127 to reestablish the RLC, the uplink control unit 103-1performs destroying of data on which the processing is not completed inthe uplink control unit 103-1, stopping or resetting of a timer, andinitialization or resetting of various parameters. Moreover, the uplinkcontrol unit 103-2 performs the same processing than the uplink controlunit 103-1, and outputs processed data to the transmission data storageunit 105-2.

The transmission data storage unit 105-1 accumulates (buffers) pieces ofdata on the logical channel, which are input from the uplink controlunit 103-1, and outputs as much data as the transmission data storageunit 105-1 is instructed to output based on an instruction from the MACcontrol unit 125-1, to the transmission HARQ processing unit 107-1.Furthermore, the transmission data storage unit 105-1 outputsinformation on an amount of data that is accumulated based on theinstruction from the MAC control unit 125-1, to the MAC control unit125-1.

In a state where data on the logical channel is not present, in a casewhere data on a new logical channel is input from the uplink controlunit 103-1, the transmission data storage unit 105-1 notifies the MACcontrol unit 125-1 that new data occurs. Furthermore, in a case wherethe data on the logical channel that has a higher priority level thanthe accumulated pieces of data on the logical channel is input from theuplink control unit 103-1, the transmission data storage unit 105-1notifies the MAC control unit 125-1 that data which has a high prioritylevel occurs. The transmission data storage unit 105-2 performs the sameprocessing than the transmission data storage unit 105-1, and processesdata that is input from the uplink control unit 103-2.

The transmission HARQ processing unit 107-1 performs coding on data thatis input from the transmission data storage unit 105-1, and performspuncture processing on the coded data. Then, the transmission HARQprocessing unit 107-1 outputs punctured data to the transmissionprocessing unit 109-1, and retains the coded data. In a case where thetransmission HARQ processing unit 107-1 is instructed by the MAC controlunit 125-1 to retransmit data, the transmission HARQ processing unit107-1 performs different puncture from the puncture that is previouslyperformed, referring to the coded data that is retained, and outputs thepunctured data to the transmission processing unit 109-1.

The transmission HARQ processing unit 107-2 performs the same processingthan the transmission HARQ processing unit 107-1, processes the datathat is input from the transmission data storage unit 105-2, and outputthe processed data to the transmission processing unit 109-2.

The transmission processing unit 109-1 performs modulation and coding ondata that is input from the transmission HARQ processing unit 107-1. Thetransmission processing unit 109-1 performs Discrete Fourier Transform(DFT)-Inverse Fast Fourier Transform (IFFT) processing on the modulatedand coded data, inserts cyclic prefix (CP) after the processing, mapspost-CP insertion data to the Physical Uplink Shared Channel (PUSCH) ineach component carrier (or cell) for the uplink, and outputs a result ofthe mapping to the radio unit 111-1.

Furthermore, in a case where the transmission processing unit 109-1 isinstructed by the PHY control unit 123-1 to provide a response toreception data, the transmission processing unit 109-1 generates an ACKor NACK signal, maps the generated signal to the Physical Uplink ControlChannel (PUCCH) in each component carrier for the uplink, and outputsthe resulting signal to radio unit 111-1. In a case where thetransmission processing unit 109-1 is instructed by the PHY control unit123-1 to transmit the Scheduling Request, the transmission processingunit 109-1 generates a scheduling request signal, maps the generatedsignal to the Physical Uplink Control Channel (PUCCH) in each componentcarrier for the uplink, and outputs the resulting signal to the radiounit 111-1.

In a case where the transmission processing unit 109-1 is instructed bythe PHY control unit 123-1 to transmit a random access preamble, thetransmission processing unit 109-1 generates the random access preamble,maps the generated signal to the Physical Random Access Channel (PRACH),and outputs the resulting signal to the radio unit 111-1. Thetransmission processing unit 109-2 performs the same processing as thetransmission processing unit 109-1, processes data that is input fromthe transmission HARQ processing unit 107-2, and outputs the processeddata to the radio unit 111-2.

The radio unit 111-1 up-converts data that is input from thetransmission processing unit 109-1, into a wireless frequency oftransmission location information (transmission cell information) thatis indicated by the PHY control unit 123-1, adjusts transmit power, andtransmits the resulting data from a transmit antenna. Furthermore, theradio unit 111-1 down-converts a wireless signal that is received from areceive antenna, and outputs the resulting signal to the receptionprocessing unit 113-1.

In the same manner, the radio unit 111-2 up-converts data that is inputfrom the transmission processing unit 109-2, into a wireless frequencyof transmission location information (transmission cell information)that is specified by the PHY control unit 123-2, adjusts transmit power,and transmits the resulting data from the transmit antenna. Furthermore,the radio unit 111-2 down-converts a wireless signal that is receivedfrom a receive antenna, and outputs the resulting signal to thereception processing unit 113-2. Moreover, frequencies that arecontrolled in the radio unit 111-1 and the radio unit 111-2 may be inthe same frequency band, and may be in different frequency bands.

The reception processing unit 113-1 performs Fast Fourier Transform(FFT) processing, decoding, demodulation processing, and the like ondata that is input from the radio unit 111-1. Among pieces ofdemodulated data, the reception processing unit 113-1 outputs data onthe Physical Downlink Shared Channel (PDSCH) to the reception HARQprocessing unit 115-1. Furthermore, among the pieces of modulated data,the reception processing unit 113-1 outputs response information(ACK/NACK) of uplink transmission data and uplink transmission approvalinformation (uplink grant) in control data that is acquired from thePhysical Downlink Control Channel (PDCCH), to the MAC control unit125-1. The reception processing unit 113-1 measures a downlink referencesignal, calculates wireless channel quality, and outputs a result of thecalculation to the MAC control unit 125-1.

Moreover, pieces of uplink transmission approval information includetransmission location information for a uplink radio resource (thePhysical Uplink Shared Channel (PUSCH)), data modulation and codingschemes, data size information, HARQ information, and the like.Furthermore, the reception processing unit 113-1 measures the downlinkreference signal, and measures the downlink wireless channel qualitybetween the base station apparatus 3-1 and the mobile station apparatus1-1. The reception processing unit 113-2 performs the same processingthan the reception processing unit 113-1, processes data that is inputfrom the radio unit 111-2, and outputs the processed data to thereception HARQ processing unit 115-2 outputs.

The reception HARQ processing unit 115-1 performs decoding processing ofthe data that is input from the reception processing unit 113-1, and ina case where the decoding processing succeeds, outputs the resultingdata to the MAC information extraction unit 117-1. In a case where thedecoding processing of the data that is input fails, the reception HARQprocessing unit 115-1 retains the data of which the decoding processingfails. In a case where data that is retransmitted is received, thereception HARQ processing unit 115-1 composites the data that isretained and the data that is retransmitted, and performs the decodingprocessing on the resulting data.

Furthermore, the reception HARQ processing unit 115-1 notifies the MACcontrol unit 125-1 whether or not the decoding processing of the datathat is input succeeds. The reception HARQ processing unit 115-2performs the same processing as the reception HARQ processing unit115-1, processes data that is input from the reception processing unit113-2, and outputs the processed data to the MAC information extractionunit 117-2.

The MAC information extraction unit 117-1 extracts control data on theMedium Access Control Layer (MAC layer) from the data that is input fromthe reception HARQ processing unit 115-1, and outputs the extractedcontrol information to the MAC control unit 125-1. The MAC informationextraction unit 117-1 outputs the remaining data to the downlink controlunit 119-1. The MAC information extraction unit 117-2 performs the sameprocessing as the MAC information extraction unit 117-1, processes datathat is input from the reception HARQ processing unit 115-2, and outputsthe processed data to the downlink control unit 119-2.

The downlink control unit 119-1 has a function of the RLC layer, andperforms processing that is input from MAC information extraction unit117-1, such as the data segmentation and concatenation. The downlinkcontrol unit 119-1 outputs the processed data to the downlink dataprocessing unit 121. The downlink control unit 119-2 performs the sameprocessing as the downlink control unit 119-1, processes data that isinput from the MAC information extraction unit 117-1, and outputs theprocessed data to the downlink data processing unit 121.

The downlink data processing unit 121 has a function of the PDCP layer,performs a function of decompressing (restoring) a compressed IP headand a function of decoding encrypted data, and performs the processingsuch as the data segmentation and concatenation. The downlink dataprocessing unit 121 performs division into an RRC message and a userdata, and outputs the RRC message to the RRC control unit 127, andoutputs the user data to the higher layer.

Based on the instruction from the MAC control unit 125-1, the PHYcontrol unit 123-1 controls the transmission processing unit 109-1, theradio unit 111-1, and the reception processing unit 113-1. The PHYcontrol unit 123-1 notifies the transmission processing unit 109-1 ofthe modulation and coding schemes that are notified by the MAC controlunit 125-1, and the modulation and coding schemes and the transmissionlocation that come from the transmit power information and thetransmission location information (the transmission cell information),and notifies the radio unit 111-1 of the frequency information and thetransmit power information on the transmission cell.

In the same manner, based on the instruction from the MAC control unit125-2, the PHY control unit 123-2 controls the transmission processingunit 109-2, the radio unit 111-2, and the reception processing unit113-2. The PHY control unit 123-2 notifies the transmission processingunit 109-2 of the modulation and coding schemes that are notified by theMAC control unit 125-2, and the modulation and coding schemes and thetransmission location that come from the transmit power information andthe transmission location information (the transmission cellinformation), and notifies the radio unit 111-2 of the frequencyinformation and the transmit power information on the transmission cell.

The MAC control unit 125-1 determines a data transmission destinationand data transmission priority based on data control configuration thatis designated by the RRC control unit 127, information on an amount ofdata, which is acquired from the transmission data storage unit 105-1,and the uplink transmission approval information that is acquired fromthe reception processing unit 113-1, and notifies the transmission datastorage unit 105-1 of information relating to data that is to betransmitted. Furthermore, the MAC control unit 125-1 notifies thetransmission HARQ processing unit 107-1 of HARQ information, and outputsthe modulation and coding schemes and the transmission locationinformation to the PHY control unit 123-1.

When a change in a state where pieces of data are accumulated isnotified by the transmission data storage unit 105-1, the MAC controlunit 125-1 triggers the Buffer Status Report. In a state where theBuffer Status Report is triggered, in a case where the uplinktransmission approval information is acquired from the receptionprocessing unit 113-1, the MAC control unit 125-1 instructs thetransmission data storage unit 105-1 to report an amount of accumulateddata on each logical channel.

When information on the amount of accumulated data on each logicalchannel is acquired from the transmission data storage unit 105-1, theMAC control unit 125-1 creates the Buffer Status Report, and outputs thecreated Buffer Status Report to the transmission data storage unit105-1.

In the state where the Buffer Status Report is triggered, in a casewhere the uplink transmission approval information is not acquired, theMAC control unit 125-1 determines transmission of the SchedulingRequest, and instructs the PHY control unit 123-1 to transmit theScheduling Request. In a case where the uplink transmission approvalinformation corresponding to the Scheduling Request is acquired, the MACcontrol unit 125-1 creates the Buffer Status Report, and outputs thecreated Buffer Status Report to the transmission data storage unit105-1.

Although the number of times that the Scheduling Request is transmittedis counted and the number of times that the Scheduling Request istransmitted reaches the maximum number of times of transmission, in acase where the uplink transmission approval information is not acquired,the MAC control unit 125-1 instructs the PHY control unit 123-1 totransmit information the random access preamble. Furthermore, the MACcontrol unit 125-1 notifies the RRC control unit 127 of release of theuplink radio resource that is allocated to the mobile station apparatusitself in which the MAC control unit 125-1 is included.

In a case where a preamble number and a random access channel number arenotified by the RRC control unit 127 or the reception processing unit113-1, the MAC control unit 125-1 starts the random access procedure,and instructs the PHY control unit 123-1 to transmit the random accesspreamble. Furthermore, the MAC control unit 125-1 notifies the PHYcontrol unit 123-1 of random access response identification information,and instructs the PHY control unit 123-1 to monitor the random accessresponse identification information.

When a random access response message is acquired, the MAC control unit125-1 outputs transmission timing information that is included in therandom access response message, to the PHY control unit 123-1. In a casewhere the random access response message is not acquired, the MACcontrol unit 125-1 again instructs the PHY control unit 123-1 totransmit the random access preamble. In a case where the number of timesthat the random access preamble is transmitted reaches the maximumnumber of times of transmission, the MAC control unit 125-1 notifies theRRC control unit 127 of a random access failure (or a random accessproblem).

The MAC control unit 125-1 acquires response information in response tothe uplink transmission data from the reception processing unit 113-1,and in a case where the response information indicates the NACK(negative response), instructs the transmission HARQ processing unit107-1 and the PHY control unit 123-1 to perform retransmission. In acase where information on whether the decoding processing of datasucceeds or fails is acquired from the reception HARQ processing unit115-1, the MAC control unit 125-1 instructs the PHY control unit 123-1to transmit the ACK or NACK signal.

Furthermore, activation/deactivation instruction information anddiscontinuous reception (DRX) control information on a cell (or, acomponent carrier) is acquired from MAC control information that isinput from the MAC information extraction unit 117-1, in order toperform activation/deactivation control and DRX control, the MAC controlunit 125-1 instructs the PHY control unit 123-1 to perform control ofthe radio unit 111-1, the transmission processing unit 109-1, and thereception processing unit 113-1.

The MAC control unit 125-1 manages enablement and disablement of anuplink transmission timing, using a transmission timing timer. The MACcontrol unit 125-1 has a transmission timing timer for every cell orevery transmission timing group, and starts or restarts the transmissiontiming timer that corresponds to a case where transmission timinginformation is applied to every cell or every transmission timing group.In a case where the transmitting timing timer expires, the MAC controlunit 125-1 stops uplink transmission to a cell for which thetransmission timing timer expires.

The MAC control unit 125-1 outputs to the PHY control unit 123-1 thetransmission timing information in the MAC control information that isinput from the MAC information extraction unit 117-1. The MAC controlunit 125-1 manages an uplink transmission timing, and controls the PHYcontrol unit 123-1.

In a case where a change in reception quality that is acquired from thereception processing unit 113-1 occurs or where a timer associated withthe Power Headroom Report expires, the MAC control unit 125-1 triggersthe Power Headroom Report. In a state where the Power Headroom Report istriggered, in a case where the uplink transmission approval informationis present, the MAC control unit 125-1 creates the Power Headroom Reportand outputs the created Power Headroom Report to the transmission datastorage unit 105-1.

In a case where the RRC control unit 127 provides an instruction for MACreset, the MAC control unit 125-1 stops or resets a timer (for example,a timer associated with the Buffer Status Report, a timer associatedwith the Power Headroom Report, or the transmission timing timer) inoperation, and cancels various types of triggering (for example,triggering associated with the Buffer Status Report or triggeringassociated with the Power Headroom Report). Furthermore, the MAC controlunit 125-1 flushes data that is retained in the transmission HARQprocessing unit 107-1 and the reception HARQ processing unit 115-1.Furthermore, the MAC control unit 125-1 performs processing, such asdeleting the preamble number and the random access channel number thatare notified, and stopping the random access procedure in operation.

The MAC control unit 125-2 performs the same processing as the MACcontrol unit 125-1, and controls the transmission data storage unit105-2, the transmission HARQ processing unit 107-2, the reception HARQprocessing unit 115-2, the MAC information extraction unit 117-2, andthe PHY control unit 123-2.

The RRC control unit 127 performs various configurations for performingcommunication between the base station apparatus 3-1 and the basestation apparatus 3-2, such as cell (base station apparatus) selection,processing that makes or releases an RRC connection to the base stationapparatus 3-1, a carrier aggregation configuration, a dual connectivityconfiguration, and data control configurations of the control data orthe user data. The RRC control unit 127 performs exchanging ofinformation between the RRC control unit 127 itself and the higher layerthat accompanies the various configurations, and performs control of thelower layer that accompanies the various configurations.

The RRC control unit 127 manages radio resource for each cell, which isallocated by the base station apparatus 3-1.

The RRC control unit 127 creates an RRC message, and outputs the createdRRC message to the uplink data processing unit 101. The RRC control unit127 interprets the RRC message that is input from the downlink dataprocessing unit 121.

The RRC control unit 127 outputs information indispensable for the PDCPlayer to the uplink data processing unit 101 and the downlink dataprocessing unit 121, and outputs information indispensable for the RLClayer to the uplink control unit 103-1, the uplink control unit 103-2,the downlink control unit 119-1, and the downlink control unit 119-2.Furthermore, the RRC control unit 127 outputs information indispensablefor the MAC layer to the MAC control unit 125-1 or the MAC control unit125-2, and outputs information indispensable for the physical layer tothe PHY control unit 123-1 or the PHY control unit 123-2.

In a case where data control configuration information is acquired suchas the logical channel for each piece of data, a priority level of thelogical channel for each piece of data, information indicating arelationship between the logical channel for each piece of control dataand the logical channel group, and information on relationship betweenthe base station apparatus (the cell or the cell group) and the logicalchannel, the RRC control unit 127 outputs data transmission controlconfiguration information to the MAC control unit 125. Furthermore, in acase where it is recognized that the communication between the basestation apparatus 3-1 and the base station apparatus 3-2 is performedusing the Dual Connect, the RRC control unit 127 notifies the MACcontrol unit 125 that the Dual Connect is in a state of being inoperation.

In a case where the RLC failure is notified by the uplink control unit103-1, the RRC control unit 127 releases a connection to the basestation apparatus 3-1, makes a cell selection, and starts processingthat makes a connection to the base station apparatus in the selectedcell.

In a case where the RLC failure is notified by the uplink control unit103-2, the RRC control unit 127 instructs the uplink data processingunit to destroy data for the base station apparatus 3-2. The RRC controlunit 127 instructs the uplink control unit 103-2 to perform RLCre-establishment by the uplink control unit 103-2. The RRC control unit127 instructs the MAC control unit 125-2 to perform the MAC reset.

Furthermore, in the case where the uplink radio resource, such as thePhysical Uplink Control Channel (PUCCH) or the uplink reference signalthat is allocated to the cell of the base station apparatus 3-2 isretained, the RRC control unit 127 releases the uplink radio resourcethat is a target. The RRC control unit 127 deletes (or releases)information (the physical random access configuration information or therandom access procedure configuration information) for executing therandom access procedure for a cell that is a target.

In a case where the random access failure is notified by the MAC controlunit 125-1, the RRC control unit 127 determines the connection to thebase station apparatus 3-1, makes the cell selection, and starts theprocessing that makes the connection to the base station apparatus inthe selected cell.

In a case where the random access failure is notified by the MAC controlunit 125-2, the RRC control unit 127 instructs the uplink dataprocessing unit to destroy the data for the base station apparatus 3-2.The RRC control unit 127 instructs the uplink control unit 103-2 toperform RLC re-establishment by the uplink control unit 103-2. The RRCcontrol unit 127 instructs the MAC control unit 125-2 to perform the MACreset by the MAC control unit 125-2.

Furthermore, in the case where the uplink radio resource, such as thePhysical Uplink Control Channel (PUCCH) or the uplink reference signalthat is allocated to the cell of the base station apparatus 3-2 isretained, the RRC control unit 127 releases the uplink radio resourcethat is a target. The RRC control unit 127 deletes the information (thephysical random access configuration information or the random accessprocedure configuration information) for executing the random accessprocedure for the cell that is a target.

In a case where release of the uplink radio resource is notified by theMAC control unit 125-1 or the MAC control unit 125-2, the RRC controlunit 127 releases an uplink radio resource, such as the Physical UplinkControl Channel (PUCCH) or the uplink reference signal that is allocatedto the cell that is a target.

Moreover, the transmission processing unit 109-1, the transmissionprocessing unit 109-2, the radio unit 111-1, the radio unit 111-2, thereception processing unit 113-1, the reception processing unit 113-2,the PHY control unit 123-1, and the PHY control unit 123-2 performoperation of the Physical Layer. The transmission data storage unit105-1, the transmission data storage unit 105-2, the transmission HARQprocessing unit 107-1, the transmission HARQ processing unit 107-2, thereception HARQ processing unit 115-1, the reception HARQ processing unit115-2, the MAC information extraction unit 117-1, the MAC informationextraction unit 117-2, the MAC control unit 125-1, and the MAC controlunit 125-2 perform operation of the MAC layer.

The uplink control unit 103-1, the uplink control unit 103-2, thedownlink control unit 119-1, and the downlink control unit 119-2performs operation of the RLC layer. The uplink data processing unit 101and the downlink data processing unit 121 performs operation of the PDCPlayer, and the RRC control unit 127 performs operation of the RRC layer.

FIG. 2 is a diagram illustrating a constitution of a base stationapparatus according to the embodiment of the present invention. The basestation apparatus 3-1 is constituted from a downlink data processingunit 201, a downlink control unit 203, a transmission data storage unit205, a transmission HARQ processing unit 207, a transmission processingunit 209, a radio unit 211, a reception processing unit 213, a receptionHARQ processing unit 215, a MAC information extraction unit 217, anuplink control unit 219, an uplink data processing unit 221, a PHYcontrol unit 223, a MAC control unit 225, an RRC control unit 227, aninter-base station apparatus communication unit 229, an MMEcommunication unit 231, and a GW communication unit 233.

The user data from the GW communication unit 233 and the control datafrom the RRC control 227 are input from the downlink data processingunit 201. The downlink data processing unit 201 has a function of thePDCP layer. The downlink data processing unit 201 performs theprocessing operations, such as the head compression of or the dataencryption of the IP packet of the user data, the data segmentation andconcatenation, and adjusts the data size. The downlink data processingunit 201 outputs data on which the processing is performed, to thedownlink control unit 203 or the inter-base station apparatuscommunication unit 229.

Moreover, the downlink data processing unit 201 outputs data to thedownlink control unit 203 or the inter-base station apparatuscommunication unit 229, taking into consideration at least one ofdownlink wireless channel quality information, an amount of downlinkdata for the mobile station apparatus 1-1, and an amount of transmissiondata (an amount of traffic) for all mobile station apparatuses in thebase station apparatus 3-1 or the base station apparatus 3-2.

The downlink control unit 203 has a function of the RLC layer. Thedownlink control unit 203 performs the processing, such as the datasegmentation and concatenation, on data that is input from the downlinkdata processing unit 201, and adjusts the data size. Furthermore, thedownlink control unit 203 performs the retransmission on specific data.The downlink control unit 203 outputs the data on which the processingis performed, to the transmission data storage unit 205.

The transmission data storage unit 205 accumulates pieces of data thatare input from the downlink control unit 203, for every user, andoutputs as much data as the transmission data storage unit 205 isinstructed to output based on an instruction from the MAC control unit225, to the transmission HARQ processing unit 207. Furthermore, thetransmission data storage unit 205 outputs information on an amount ofdata that is accumulated, to the MAC control unit 225.

The transmission HARQ processing unit 207 performs the coding on datathat is input, and performs the puncture processing on the coded data.Then, the transmission HARQ processing unit 207 outputs punctured datato the transmission processing unit 209, and retains the coded data. Ina case where the transmission HARQ processing unit 207 is instructed bythe MAC control unit 225 to retransmit data, the transmission HARQprocessing unit 207 performs different puncture from the puncture thatis previously performed, referring to the coded data that is retained,and outputs the punctured data to the transmission processing unit 209.

The transmission processing unit 209 performs the modulation and codingon data that is input from the transmission HARQ processing unit 207.The transmission processing unit 209 maps the modulated and coded datato a signal and each channel, such as the Physical Downlink ControlChannel (PDCCH), the downlink synchronizing signal, the PhysicalBroadcast Channel (PBCH), and the Physical Downlink Shared Channel(PDSCH), for each cell, performs the OFDM signal processing, such as theserial/parallel conversion, the Inverse Fast Fourier Transform (IFFT),and the CP insertion, on data that results from the mapping, andgenerates an OFDM signal.

Then, the transmission processing unit 209 outputs the generated OFDMsignal to the radio unit 211. Furthermore, in a case where thetransmission processing unit 209 is instructed by the MAC control unit225 to provide a response to reception data, the transmission processingunit 209 generates the ACK or NACK signal, maps the generated signal tothe Physical Downlink Control Channel (PDCCH), and outputs the resultingsignal to the radio unit 211. The transmission processing unit 209 mapsthe uplink transmission approval information that is notified by the PHYcontrol unit 223, to the Physical Downlink Control Channel (PDCCH), andoutputs the resulting information to the radio unit 211.

The radio unit 211 up-converts data that is input from the transmissionprocessing unit 209, into a wireless frequency, adjusts the transmitpower, and transmits the resulting data from the transmit antenna.Furthermore, the radio unit 211 down-converts a wireless signal that isreceived from the receive antenna, and outputs the resulting signal tothe reception processing unit 213. The reception processing unit 213performs the Fast Fourier Transform (FFT) processing, the decoding, thedemodulation processing, and the like on a signal that is input from theradio unit 211.

Among pieces of demodulated data, the reception processing unit 213outputs data on the Physical Uplink Shared Channel (PUSCH) to thereception HARQ processing unit 215. Furthermore, among the pieces ofmodulated data, the reception processing unit 213 outputs responseinformation (ACK/NACK) of downlink transmission data, downlink wirelesschannel quality information (CQI), and uplink transmission requestinformation (the Scheduling Request) in control data that is acquiredfrom the Physical Uplink Control Channel (PUCCH), to the MAC controlunit 225. Furthermore, the reception processing unit 213 measures theuplink reference signal, and measures the uplink wireless channelquality between the base station apparatus 3-1 and the mobile stationapparatus 1-1.

The reception HARQ processing unit 215 performs the decoding processingof the data that is input from the reception processing unit 213, and inthe case where the decoding processing succeeds, outputs the resultingdata to the MAC information extraction unit 217. In the case where thedecoding processing of the data that is input fails, the reception HARQprocessing unit 215 retains the data of which the decoding processingfails. In the case where the data that is retransmitted is received, thereception HARQ processing unit 215 composites the data that is retainedand the data that is retransmitted, and performs the decoding processingon the resulting data. Furthermore, the reception HARQ processing unit215 notifies the MAC control unit 225 whether or not the decodingprocessing of the data that is input succeeds.

The MAC information extraction unit 217 extracts control data on the MAClayer from the data that is input from the reception HARQ processingunit 215, and outputs the extracted control data to the MAC control unit225. The MAC information extraction unit 217 outputs the remaining datato the uplink control unit 219. Pieces of control data on the MAC layerinclude the Buffer Status Report and the like.

The uplink control unit 219 has the function of the RLC layer. Theuplink control unit 219 performs the processing, such as the datasegmentation and concatenation, on data that is input from the MACinformation extraction unit 217, and adjusts the data size. Furthermore,the uplink control unit 219 performs the retransmission on specificdata. The uplink control unit 219 outputs the processed data to theuplink data processing unit 221.

The uplink data processing unit 221 has the function of the PDCP layer.The uplink data processing unit 221 performs the function ofdecompressing (restoring) a compressed IP head and the function ofdecoding encrypted data, and performs the processing such as the datasegmentation and concatenation. The uplink data processing unit 221performs the division into the RRC message and the user data, andoutputs the RRC message to the RRC control unit 227, and outputs theuser data to the GW communication unit 233.

Based on the instruction from the MAC control unit 225, the PHY controlunit 223 controls the transmission processing unit 209, the radio unit211, and the reception processing unit 213. The PHY control unit 223creates uplink transmission approval information from a result of uplinkscheduling, which is notified by the MAC control unit 225, and notifiesthe transmission processing unit 209 of the created uplink transmissionapproval information.

The MAC control unit 225 has the function of the MAC layer. The MACcontrol unit 225 performs control of the MAC layer based on informationthat is acquired from the RRC control unit 227, the lower layer, or thelike. The MAC control unit 225 performs the scheduling processing ofdata that is transmitted in the downlink and the uplink. The MAC controlunit 225 performs the scheduling processing of the downlink data,referring to the response information (ACK/NACK) of the downlinktransmission data and the downlink wireless channel quality information(CQI), which are input from the reception processing unit 213, andinformation on an amount of data for every user, which is acquired fromthe transmission data storage unit 205. Based on a result of thescheduling processing, the MAC control unit 225 controls thetransmission data storage unit 205, the transmission HARQ processingunit 207, and the transmission processing unit 209.

The MAC control unit 225 performs the scheduling processing of theuplink data, referring to the uplink transmission information (theScheduling Request), which is input from the reception processing unit213, and the Buffer Status Report and the Power Headroom Report, whichare input from the MAC information extraction unit 217. The MAC controlunit 225 notifies the PHY control unit 223 of a result of the schedulingprocessing.

Furthermore, the MAC control unit 225 acquires the response informationin response to the uplink transmission data from the receptionprocessing unit 213, and in the case where the response informationindicates the NACK (negative response), instructs the transmission HARQprocessing unit 207 and the transmission processing unit 209 to performthe retransmission. In a case where the information on whether thedecoding processing of data succeeds or fails is acquired from thereception HARQ processing unit 215, the MAC control unit 225 instructsthe transmission processing unit 209 to transmit the ACK or NACK signal.

Furthermore, the MAC control unit 225 performs activation/deactivationprocessing of a cell (or a component carrier) that is allocated to themobile station apparatus 1-1. The MAC control unit 225 performs themanagement and the like of the transmission timing group and the uplinktransmission timing in each transmission timing group.

The RRC control unit 227 performs various configurations for performingcommunication with the mobile station apparatus 1-1, such as theprocessing that makes or releases the RRC connection to the mobilestation apparatus 1-1, handover processing, the Carrier Aggregationconfiguration, the dual connectivity configuration, and the data controlconfiguration for which cell (or which base station apparatus) is usedto transmit and receive control data and user data of the mobile stationapparatus 1-1 at the time of the Dual Connect, performs exchanging ofinformation between the RRC control unit 227 itself and the higher layerthat accompanies the various configuration, and performs control of thelower layer that accompanies the various configurations.

The RRC control unit 227 creates various RRC messages, and outputs thecreated RRC messages to the downlink data processing unit 201. The RRCcontrol unit 227 interprets the RRC message that is input from theuplink data processing unit 221.

The RRC control unit 227 outputs the information indispensable for thePDCP layer to the downlink data processing unit 201 and the uplink dataprocessing unit 221, and outputs the information indispensable for theRLC layer to the downlink control unit 203 and the uplink control unit219.

Furthermore, the RRC control unit 227 outputs the informationindispensable for the MAC layer to the MAC control unit 225, and outputsthe information indispensable for the physical layer to the PHY controlunit 223. Furthermore, in a case where the handover or the Dual Connectis performed, the RRC control unit 227 notifies informationindispensable for the inter-base station apparatus communication unit229 and the MME communication unit 231.

The inter-base station apparatus communication unit 229 makes aconnection to a different base station apparatus (the base stationapparatus 3-2), and transmits a control message between the base stationapparatuses, which is input from the RRC control unit 227, to the basestation apparatus 3-2. Furthermore, the inter-base station apparatuscommunication unit 229 receives the control message between the basestation apparatuses from the base station apparatus 3-2, and outputs thereceived control message to the RRC control unit 227. Control messagesbetween the base station apparatuses include a message relating to thehandover, a control message relating to a connection for the DualConnect and release of the connection for the Dual Connect, a messagerelating to data control by the mobile station apparatus 1-1, and thelike.

Furthermore, the inter-base station apparatus communication unit 229transmits downlink user data of the mobile station apparatus 1-1 thatperforms the Dual Connect, to the base station apparatus 3-2. Theinter-base station apparatus communication unit 229 receives uplink userdata of the mobile station apparatus 1-1 that performs the Dual Connect,from the base station apparatus 3-2, and outputs the received data tothe uplink data processing unit 221.

The MME communication unit 231 makes a connection to the MobilityManagement Entity (MME), and transmits a control message (an S1 message)between the base station apparatus and the MME, which is input from theRRC control unit 227, to the MME. Furthermore, the MME communicationunit 231 receives the control message between the base station apparatusand the MME from the MME, and outputs the received control message tothe RRC control unit 227. The control messages between the base stationapparatus and the MME include the path switch request message, the pathswitch request response message, and the like.

The inter-GW communication unit 233 makes a connection to the gateway(GW), receives the user data of the mobile station apparatus 1-1, whichis sent from the GW, and outputs the received data to the downlink dataprocessing unit 201. Furthermore, the inter-GW communication unit 233transmits the user data of the mobile station apparatus 1-1, which isinput from the uplink data processing unit 221, to the GW.

Moreover, the transmission processing unit 209, the radio unit 211, thereception processing unit 213, and the PHY control unit 223 perform theoperation of the PHY layer. The transmission data storage unit 205, thetransmission HARQ processing unit 207, the reception HARQ processingunit 215, the MAC information extraction unit 217, and the MAC controlunit 225 perform the operation of the MAC layer. The downlink controlunit 203 and the uplink control unit 219 performs the operation of theRLC layer. The downlink data processing unit 201 and the uplink dataprocessing unit 221 perform the operation of the PDCP layer. The RRCcontrol unit 227 performs the operation of the RRC layer.

FIG. 3 is a diagram illustrating a constitution of a base stationapparatus according to the embodiment of the present invention. The basestation apparatus 3-2 is constituted from a downlink control unit 301, atransmission data storage unit 303, a transmission HARQ processing unit305, a transmission processing unit 307, a radio unit 309, a receptionprocessing unit 311, a reception HARQ processing unit 313, a MACinformation extraction unit 315, an uplink control unit 317, a PHYcontrol unit 319, a MAC control unit 321, an RRC control unit 323, aninter-base station apparatus communication unit 325, and an MMEcommunication unit 327.

The user data from the inter-base station apparatus communication unit325 is input into the downlink control unit 301. The downlink controlunit 301 has the function of the RLC layer, performs the processing,such as the data segmentation and concatenation, on data that is inputfrom the inter-base station apparatus communication unit 325, andadjusts the data size. Furthermore, the downlink control unit 301performs the retransmission on specific data. The downlink control unit301 outputs the data on which the processing is performed, to thetransmission data storage unit 303.

The transmission data storage unit 303 accumulates pieces of data thatare input from the downlink control unit 301, for every user, andoutputs as much data as the transmission data storage unit 303 isinstructed to output based on an instruction from the MAC control unit321, to the transmission HARQ processing unit 305. Furthermore, thetransmission data storage unit 303 outputs information on an amount ofdata that is accumulated, to the MAC control unit 321.

The transmission HARQ processing unit 305 performs the coding on datathat is input, and performs the puncture processing on the coded data.Then, the transmission HARQ processing unit 305 outputs punctured datato the transmission processing unit 307, and retains the coded data. Ina case where the transmission HARQ processing unit 305 is instructed bythe MAC control unit 321 to retransmit data, the transmission HARQprocessing unit 305 performs different puncture from the puncture thatis previously performed, referring to the coded data that is retained,and outputs the punctured data to the transmission processing unit 307.

The transmission processing unit 307 performs the modulation and codingon data that is input from the transmission HARQ processing unit 305.The transmission processing unit 307 maps the modulated and coded datato a signal and each channel, such as the Physical Downlink ControlChannel (PDCCH), the downlink synchronizing signal, the PhysicalBroadcast Channel (PBCH), and the Physical Downlink Shared Channel(PDSCH), for each cell, performs the OFDM signal processing, such as theserial/parallel conversion, the Inverse Fast Fourier Transform (IFFT),and the CP insertion, on data that results from the mapping, andgenerates an OFDM signal.

Then, the transmission processing unit 307 outputs the generated OFDMsignal to the radio unit 309. Furthermore, in a case where thetransmission processing unit 307 is instructed by the MAC control unit321 to provide a response to reception data, the transmission processingunit 307 generates the ACK or NACK signal, maps the generated signal tothe Physical Downlink Control Channel (PDCCH), and outputs the resultingsignal to the radio unit 309. The transmission processing unit 307 mapsthe uplink transmission approval information that is notified by the PHYcontrol unit 319, to the Physical Downlink Control Channel (PDCCH), andoutputs the resulting information to the radio unit 309.

The radio unit 309 up-converts data that is input from the transmissionprocessing unit 307, into a wireless frequency, adjusts the transmitpower, and transmits the resulting data from the transmit antenna.Furthermore, the radio unit 309 down-converts a wireless signal that isreceived from the receive antenna, and outputs the resulting signal tothe reception processing unit 311. The reception processing unit 311performs the Fast Fourier Transform (FFT) processing, the decoding, thedemodulation processing, and the like on a signal that is input from theradio unit 309.

Among pieces of demodulated data, the reception processing unit 311outputs data on the Physical Uplink Shared Channel (PUSCH) to thereception HARQ processing unit 313. Furthermore, among the pieces ofmodulated data, the reception processing unit 311 outputs responseinformation (ACK/NACK) of downlink transmission data, downlink wirelesschannel quality information (CQI), and uplink transmission requestinformation (the Scheduling Request) in control data that is acquiredfrom the Physical Uplink Control Channel (PUCCH), to the MAC controlunit 321. Furthermore, the reception processing unit 313 measures theuplink reference signal, and measures the uplink wireless channelquality between the base station apparatus 3-2 and the mobile stationapparatus 1-1.

The reception HARQ processing unit 313 performs the decoding processingof the data that is input from the reception processing unit 311, and inthe case where the decoding processing succeeds, outputs the resultingdata to the MAC information extraction unit 315. In the case where thedecoding processing of the data that is input fails, the reception HARQprocessing unit 313 retains the data of which the decoding processingfails. In the case where the data that is retransmitted is received, thereception HARQ processing unit 313 composites the data that is retainedand the data that is retransmitted, and performs the decoding processingon the resulting data. Furthermore, the reception HARQ processing unit313 notifies the MAC control unit 321 whether or not the decodingprocessing of the data that is input succeeds.

The MAC information extraction unit 315 extracts control data on the MAClayer from the data that is input from the reception HARQ processingunit 313, and outputs the extracted control data to the MAC control unit321. The MAC information extraction unit 315 outputs the remaining datato the uplink control unit 317. Pieces of control data on the MAC layerinclude the Buffer Status Report and the like.

The uplink control unit 317 has the function of the RLC layer. Theuplink control unit 317 performs the processing, such as the datasegmentation and concatenation, on data that is input from the MACinformation extraction unit 315, and adjusts the data size. Furthermore,the uplink control unit 317 performs the retransmission on specificdata. The uplink control unit 317 outputs the data on which theprocessing is performed, to the inter-base station apparatuscommunication unit 325.

Based on the instruction from the MAC control unit 321, the PHY controlunit 319 controls the transmission processing unit 307, the radio unit309, and the reception processing unit 311. The PHY control unit 319creates uplink transmission approval information from a result of uplinkscheduling, which is notified by the MAC control unit 321, and notifiesthe transmission processing unit 307 of the created uplink transmissionapproval information.

The MAC control unit 321 has the function of the MAC layer. The MACcontrol unit 321 performs the control of the MAC layer based oninformation that is acquired from the RRC control unit 323, the lowerlayer, or the like. The MAC control unit 321 performs the schedulingprocessing of data that is transmitted in the downlink and the uplink.The MAC control unit 321 performs the scheduling processing of thedownlink data, referring to the response information (ACK/NACK) of thedownlink transmission data and the downlink wireless channel qualityinformation (CQI), which are input from the reception processing unit311, and information on an amount of data for every user, which isacquired from the transmission data storage unit 303. Based on a resultof the scheduling processing, the MAC control unit 321 controls thetransmission data storage unit 303, the transmission HARQ processingunit 305, and the transmission processing unit 307.

The MAC control unit 321 performs the scheduling processing of theuplink data, referring to the uplink transmission information (theScheduling Request), which is input from the reception processing unit311, and the Buffer Status Report, which is input from the MACinformation extraction unit 315. The MAC control unit 321 notifies thePHY control unit 319 of a result of the scheduling processing.

Furthermore, the MAC control unit 321 acquires the response informationin response to the uplink transmission data from the receptionprocessing unit 311, and in the case where the response informationindicates the NACK (negative response), instructs the transmission HARQprocessing unit 305 and the transmission processing unit 307 to performthe retransmission. In a case where the information on whether thedecoding processing of data succeeds or fails is acquired from thereception HARQ processing unit 313, the MAC control unit 321 instructsthe transmission processing unit 307 to transmit the ACK or NACK signal.

Furthermore, the MAC control unit 321 performs theactivation/deactivation processing of a cell (or a component carrier)that is allocated to the mobile station apparatus 1-1. The MAC controlunit 321 performs the management and the like of the transmission timinggroup and the uplink transmission timing in each transmission timinggroup.

The RRC control unit 323 performs various configurations for performingcommunication with the mobile station apparatus 1-1, such as theprocessing that makes or releases the connection to the mobile stationapparatus 1-1, the carrier aggregation configuration, and the datacontrol configuration for which cell is used to transmit and receive thecontrol data and the user data of the mobile station apparatus 1-1,performs the exchanging of information between the RRC control unit 323itself and the higher layer that accompanies the various configuration,and performs control of the lower layer that accompanies the variousconfigurations.

The RRC control unit 323 creates the control message between the basestation apparatuses, and outputs the created control message to theinter-base station apparatus communication unit 325. The RRC controlunit 323 interprets the control message between the base stationapparatuses from the inter-base station apparatus communication unit325. The RRC control unit 323 outputs the information indispensable forthe MAC layer to the MAC control unit 321, and outputs the informationindispensable for the physical channel to the PHY control unit 319.Furthermore, in a case where the handover or the dual connectivity isperformed, the RRC control unit 323 notifies information necessary forthe inter-base station apparatus communication unit 325 and the MMEcommunication unit 327.

The inter-base station apparatus communication unit 325 makes aconnection to a different base station apparatus (the base stationapparatus 3-1), and transmits a control message between the base stationapparatuses, which is input from the RRC control unit 323, to the basestation apparatus 3-1. Furthermore, the inter-base station apparatuscommunication unit 325 receives the control message between the basestation apparatuses from the base station apparatus 3-1, and outputs thereceived control message to the RRC control unit 323. That is, in theDual Connect, various configurations relating to a radio link betweenthe base station apparatus 3-2 and the mobile station apparatus 1-1 isnotified to the mobile station apparatus 1-1 through the base stationapparatus 3-1. Control messages between the base station apparatusesinclude a message relating to the handover, a control message relatingto a connection for the Dual Connect and release of the connection forthe Dual Connect, a message relating to data control by the mobilestation apparatus 1-1, and the like.

Furthermore, the inter-base station apparatus communication unit 325transmits the uplink user data of the mobile station apparatus 1-1 thatperforms the Dual Connect, to the base station apparatus 3-1. Theinter-base station apparatus communication unit 325 receives thedownlink user data of the mobile station apparatus 1-1 that performs theDual Connect, from the base station apparatus 3-1, and outputs thereceived data to the downlink control unit 301.

The MME communication unit 327 makes a connection to the MobilityManagement Entity (MME), and transmits the control message between thebase station apparatus and the MME, which is input from the RRC controlunit 323, to the MME. Furthermore, the MME communication unit 327receives the control message between the base station apparatus and theMME from the MME, and outputs the received control message to the RRCcontrol unit 323. The control messages between the base stationapparatus and the MME include the path switch request message, the pathswitch request response message, and the like.

Moreover, the transmission processing unit 307, the radio unit 309, thereception processing unit 311, and the PHY control unit 319 perform theoperation of the PHY layer. The transmission data storage unit 303, thetransmission HARQ processing unit 305, the reception HARQ processingunit 313, the MAC information extraction unit 315, and the MAC controlunit 321 perform the operation of the MAC layer. The downlink controlunit 301 and the uplink control unit 317 performs the operation of theRLC layer. The RRC control unit 323 performs the operation of the RRClayer.

[Operation Description]

The wireless communication system as described referring to FIGS. 6 to13 is assumed. Then, as illustrated in FIG. 6, the base stationapparatus 3-1 and the multiple mobile station apparatuses 1-1, 1-2, and1-3 performs communication. Furthermore, the wireless communicationsystem is assumed in which the base station apparatus 3-1 in the MacroCell and the base station apparatus 3-2 in the Small Cell, which aredescribed referring to FIG. 11, and the mobile station apparatus 1-1 areset to perform the communication through multiple cells.

Furthermore, as illustrated in FIG. 13, the mobile station apparatus 1-1makes connections to the base station apparatus 3-1 and the base stationapparatus 3-2, using the Dual Connect. The transmission and reception ofthe control information (the control data) or the user information (theuser data) are performed between the base station apparatus 3-1 in theMacro Cell and the mobile station apparatus 1-1. The transmission andreception of the user information are performed between the base stationapparatus 3-2 in the Small Cell and the mobile station apparatus 1-1.

The base station apparatus 3-1 and the base station apparatus 3-2 aredescribed below as making connections to the mobile station apparatus1-1, through a cell 1 and a cell 2, respectively, for descriptions ofoperations of the base station apparatus and the mobile stationapparatus. Moreover, each base station apparatus may allocate multiplecells to the mobile station apparatus 1-1. The cell 1 (a cell group 1)and the cell 2 (a cell group 2) may be configured as a mater cell group(MCG) and a secondary cell group (SCG), respectively.

In a case where the base station apparatus 3-1 determines that in orderto perform the communication, the base station apparatus 3-1 makes aconnection to the mobile station apparatus 1-1 while making a connectionto the base station apparatus 3-2 using the Dual Connect, the basestation apparatus 3-1 transmits a dual connectivity connection requestmessage (or secondary cell group addition message) to the base stationapparatus 3-2. Included in the dual connectivity connection requestmessage are communication capability information of the mobile stationapparatus 1-1, radio resource configuration information on a cell (acell group) of the base station apparatus 3-1, which is allocated by thebase station apparatus 3-1 to the mobile station apparatus 1-1, and thelike.

When receiving the dual connectivity connection request message, thebase station apparatus 3-2 transmits a dual connectivity connectionrequest response message (or a secondary cell group amendment requestmessage) to the base station apparatus 3-1. Included in the dualconnectivity connection request response message are radio resourceconfiguration information on a cell (a cell group) of the base stationapparatus 3-2, which is allocated by the base station apparatus 3-2 tothe mobile station apparatus 1-1, and the like.

The radio resource configuration information on the cell (the cellgroup) of the base station apparatus includes radio bearer configurationinformation, physical layer configuration information, MAC layerconfiguration information, physical channel configuration information,random access procedure configuration information, and configurationinformation on the cell group. Moreover, the physical channelconfiguration information and the random access procedure configurationinformation are configuration information of every cell or every basestation apparatus, and the radio bearer configuration information, thephysical layer configuration information and the MAC layer configurationinformation are configuration information of every mobile stationapparatus.

The physical channel configuration information includes physical randomaccess channel configuration information, physical downlink sharedchannel configuration information, physical uplink shared channelconfiguration information, physical downlink control channelconfiguration information, physical uplink control channel configurationinformation, and the like. Moreover, the physical channel configurationinformation includes constitution (mapping) information on each physicalchannel of each cell, generation information on a transmit signal,demodulation information on a receive signal, and the like.

The physical layer configuration information includes allocationinformation on the Uplink Shared Channel, downlink wireless qualityreport configuration information, uplink reference signal allocationinformation, uplink transmit power information, scheduling requestconfiguration information, and the like. Moreover, the physical layerconfiguration information includes information for control of thePhysical Layer, which is allocated to the mobile station apparatus 1-1.

The MAC layer configuration information includes discontinuous receptionoperation configuration information, buffer status report configurationinformation, power headroom report configuration information,transmission timing group configuration information, transmission timingtimer configuration information, and the like.

The radio bearer configuration information includes control radio bearerinformation to be added, data radio bearer information to be added, anddata radio bearer information to be deleted. The control radio bearerinformation to be added includes logical channel configurationinformation on the radio bearer, RLC layer configuration information,and the like. The data radio bearer information to be added includeslogical channel configuration information on the radio bearer,information indicating a relationship between the radio bearer andtransmission/reception cell, RLC layer configuration information, PDCPlayer configuration information, and the like. The logical channelconfiguration information includes a priority level of the logicalchannel, information indicating a relationship between the logicalchannel and the Logical Channel Group (LCG), and the like.

Moreover, the information indicating the relationship between the radiobearer and the transmission/reception cell may be information indicatinga relationship between the radio bearer and the cell group, and may beinformation indicating a relationship between the radio bearer and theMAC layer. Furthermore, the radio bearer configuration information maybe created by the base station apparatus 3-1. Furthermore, the controlradio bearer information to be added may be set to be included only inthe radio bearer configuration information of the base station apparatus3-1 in the Macro Cell. Furthermore, the radio bearer configurationinformation may include bearer split control information on which basestation apparatus data for splitting the bearer is preferentiallytransmitted to and so forth. Furthermore, in a case where the samebearer is configured for each cell (each base station apparatus), themobile station apparatus 1-1 may recognize that such a bearer resultsfrom the Bearer Split.

When receiving the dual connectivity connection request responsemessage, the base station apparatus 3-1 transmit a dual connectivityconfiguration message (or an RRC connection reconfiguration message)indicating addition of the cell (the cell group) of the base stationapparatus 3-2, the mobile station apparatus 1-1. The dual connectivityconfiguration message includes radio resource configuration informationon the cell (the cell group) of the base station apparatus 3-2, which isincluded in the dual connectivity connection request response messageand which is allocated by the base station apparatus 3-2 to the mobilestation apparatus 1-1. Moreover, the dual connectivity configurationmessage may include radio resource configuration information on the cell(the cell group) of the base station apparatus 3-1, which is allocatedby the base station apparatus 3-1 to the mobile station apparatus 1-1.

When receiving the dual connectivity configuration message, the mobilestation apparatus 1-1 configures radio resource configurationinformation on the cell (the cell group) of the base station apparatus3-2, which is included in the dual connectivity configuration message,and transmits a dual connectivity configuration completion message (oran RRC connectivity reconfiguration completion message) to the basestation apparatus 3-1. When receiving the dual connectivityconfiguration message, the base station apparatus 3-1 transmits the dualconnectivity connection completion message (or a secondary cell groupaddition completion message) to the base station apparatus 3-2.

For example, a configuration of the radio bearer by the mobile stationapparatus 1-1 for the base station apparatus 3-1 before the dualconnectivity configuration is such that a logical channel 1 whichcorresponds to a Radio Bearer 1 (control data 1) for control is set tobe a logical channel group 1, a logical channel 2 which correspond to aRadio Bearer 2 (control data 2) for control is set to be a logicalchannel group 2, and a logical channel 3 which corresponds to a dataradio bearer 1 (user data 1) is set to be a logical channel group 3.

In a case where, with the dual connectivity configuration message, aradio bearer of the base station apparatus 3-2 is such that the logicalchannel 1 which corresponds to the data radio bearer 1 (the user data 1)is set to be the logical channel group 1, and the logical channel 2which corresponds to the data radio bearer 2 (user data 2) is set to bethe logical channel group 2, for a radio bearer of the mobile stationapparatus 1-1, the radio bearer of the mobile station apparatus 1-1 forthe base station apparatus 3-1 is such that the logical channel 1 whichcorresponds to the Radio Bearer 1 (the control data 1) for control isset to be the logical channel group 1, the logical channel 2 whichcorresponds to the Radio Bearer 2 (the control data 2) for control isset to be the logical channel group 2, and the logical channel 3 whichcorresponds to the data radio bearer (the user data 1) is set to be thelogical channel group 3. Furthermore, in such a case, for the radiobearer of the mobile station apparatus 1-1, the radio bearer of themobile station apparatus 1-1 for the base station apparatus 3-2 is suchthat a logical channel 4 which corresponds to the data radio bearer 1(the user data 1) is set to be a logical channel group 4, and a logicalchannel 5 which corresponds to the data radio bearer 2 (the user data 2)is set to be a logical channel group 5.

Moreover, the mobile station apparatus 1-1 recognizes the data radiobearer 1 as a radio bearer that results from the Bearer Split. Moreover,the base station apparatus 3-1 may send information indicating whetheror not the Bearer Split is separately performed on each radio bearer.

After transmitting the dual connectivity configuration completionmessage, the mobile station apparatus 1-1 executes the random accessprocedure on the base station apparatus 3-2, using the physical randomaccess channel configuration information in the radio resourceconfiguration information and the random access procedure configurationinformation. When completing the random access procedure for the basestation apparatus 3-2, the mobile station apparatus 1-1 and the basestation apparatus 3-2 start uplink and downlink communication.

Furthermore, in a case where the random access procedure for the basestation apparatus 3-2 is completed, the mobile station apparatus 1-1 maynotify the base station apparatus 3-1 that the random access procedurefor the base station apparatus 3-2 is completed. In a case where themobile station apparatus 1-1 notifies the base station apparatus 3-1that the random access procedure for the base station apparatus 3-2 iscompleted, the base station apparatus 3-1 starts to transfer data of themobile station apparatus 1-1, which is configured as the radio bearer ofthe base station apparatus 3-2, to the base station apparatus 3-2.

Moreover, in a case where random access dedicated configurationinformation including the preamble number and the random access channelnumber is included in the radio resource configuration information, orin a case where random access instruction information is acquired fromthe base station apparatus 3-2, the mobile station apparatus 1-1executes the random access procedure. Moreover, in a case where thepreamble number is included with the random access dedicatedconfiguration information or the random access instruction information,the Non-contention based Random Access procedure is executed.

Furthermore, the base station apparatus 3-2 may notify the base stationapparatus 3-1 that the random access procedure between the mobilestation apparatus 1-1 and the base station apparatus 3-2 is completed.After the random access response message is transmitted to the mobilestation apparatus 1-1, the base station apparatus 3-2 notifies that therandom access procedure between the mobile station apparatus 1-1 and thebase station apparatus 3-2 is completed. After it is notified by thebase station apparatus 3-2 that the random access procedure iscompleted, the base station apparatus 3-1 starts to transfer the data ofthe mobile station apparatus 1-1, which is configured as the radiobearer of the base station apparatus 3-2, to the base station apparatus3-2.

In a case where the random access procedure for the base stationapparatus 3-2 fails (or in a case where the random access procedure forthe base station apparatus 3-2 is not completed), the mobile stationapparatus 1-1 notifies the base station apparatus 3-1 of the failure ofthe random access procedure (or the problem with the random access to)for the base station apparatus 3-2. Moreover, in a case where the numberof times that the random access preamble is transmitted is equal to orgreater than the maximum number of times that the random access preambleis transmitted, which is indicated with the random access procedureconfiguration information, the mobile station apparatus 1-1 determinesthat the random access fails.

Then, the mobile station apparatus 1-1 is set not to perform the uplinktransmission to the base station apparatus 3-2. Moreover, the mobilestation apparatus 1-1 may be set not to perform a downlink receptionoperation on the base station apparatus 3-2.

More specifically, operation of the mobile station apparatus 1-1 isdescribed. When receiving the dual connectivity configuration message(or the RRC connection reconfiguration message), with regard to the RRClayer of the mobile station apparatus 1-1, the mobile station apparatus1-1 configures pieces of radio resource configuration information of thebase station apparatus 3-2 for suitable layers, that is, the PHY layer,the MAC layer, the RLC layer, the PDCP layer, and the RRC layer,respectively. Furthermore, with regard to the RRC layer of the mobilestation apparatus 1-1, as a configuration of the data radio bearer, thelogical channel configuration information on the radio bearer and theinformation indicating the relationship between the radio bearer and thetransmission/reception cell is configured for the PDCP layer and the RLClayer, the PDCP layer configuration information is configured for thePDCP layer, and the RLC layer configuration information is configuredfor the RLC layer.

With regard to a constitution of a communication protocol for the mobilestation apparatus 1-1 in a dual connectivity state as illustrated inFIG. 13, multiple PHY layers, multiple Mac layers, and multiple RLClayers each may be constituted to be present in a manner thatcorresponds to each base station apparatus. More precisely, asillustrated in FIG. 4, for the constitution of the communicationprotocol, the mobile station apparatus 1-1 may be constituted to havethe PHY layer (a PHY layer 1), the MAC layer (a MAC layer 1), and theRLC layer (an RLC layer 1) that correspond to the base station apparatus3-1 (or the master cell group), and the PHY layer (a PHY layer 2), theMAC layer (a MAC layer 2), and the RLC layer (an RLC layer 2) thatcorrespond to the base station apparatus 3-2 (or the secondary cellgroup).

More precisely, as illustrated in FIG. 12, for the constitution of thecommunication protocol, the mobile station apparatus 1-1 in the dualconnectivity state may be constituted to have the PHY layer (a PHY layer3), the MAC layer (a MAC layer 3), the RLC layer (a RLC layer 3), thePDCP layer (a PDCP layer 3) that correspond to the base stationapparatus 3-1 (or the master cell group), and the PHY layer (a PHY layer4), the MAC layer (a MAC layer 4), the RLC layer (an RLC layer 4), andthe PDCP layer (a PDCP layer 4) that correspond to the base stationapparatus 3-2 (or the secondary cell group).

The RRC layer of the mobile station apparatus 1-1 creates the dualconnectivity configuration completion message after configuring theradio resource, and provide a notification to the PDCP layer 1 of themobile station apparatus 1-1 in order to transmit the created message tothe base station apparatus 3-1. The created message is processed in thePDCP layer 1 of the mobile station apparatus 1-1, the RLC layer (the RLClayer 1) of the mobile station apparatus 1-1, which corresponds to thebase station apparatus 3-1, the MAC layer (the MAC layer 1) of themobile station apparatus 1-1, which corresponds to the base stationapparatus 3-1, and the PHY layer (the PHY layer 1) of the mobile stationapparatus 1-1, which corresponds to the base station apparatus 3-1, andis transmitted to the base station apparatus 3-1.

After the dual connectivity configuration completion message istransmitted, in a case where the random access dedicated configurationinformation including the preamble number and the random access channelnumber is included in the radio resource configuration information, theRRC layer of the mobile station apparatus 1-1 notifies the MAC layer(the MAC layer 2) of the mobile station apparatus 1-1, which correspondsto the base station apparatus 3-2, of the preamble number and the randomaccess channel number.

When the preamble number and the random access channel number arenotified, the MAC layer 2 of the mobile station apparatus 1-1 starts theNon-contention based Random Access procedure. The MAC layer 2 of themobile station apparatus 1-1 calculates random access identificationinformation for reception of the random access response, from thenotified random access channel number. Then, the MAC layer 2 of themobile station apparatus 1-1 notifies the PHY layer (the PHY layer 2) ofthe mobile station apparatus 1-1, which corresponds to the base stationapparatus 3-2, of the preamble number, the random access channel number,and the random access identification information.

The PHY layer 2 of the mobile station apparatus 1-1 generates the randomaccess preamble from the notified preamble number and the physicalrandom access channel configuration information, and transmits therandom access preamble in a random access channel position that isnotified. After the random access preamble is transmitted, the PHY layer2 of the mobile station apparatus 1-1 monitors the random accessidentification information that is notified on the Physical DownlinkControl Channel (PDCCH).

In a case where the random access identification information that isnotified on the Physical Downlink Control Channel (PDCCH) is detected,the PHY layer 2 of the mobile station apparatus 1-1 receives the randomaccess response message that is allocated to the Physical DownlinkShared Channel (PDSCH), and notifies the MAC layer 2 of the mobilestation apparatus 1-1 of the received random access response message.

When the random access response message is acquired, the MAC layer 2 ofthe mobile station apparatus 1-1 checks whether or not the preamblenumber of the received random access response message is included in therandom access response message. In a case where the preamble number isincluded in the random access response message, the MAC layer 2 of themobile station apparatus 1-1 configures the transmission timinginformation that is included in the random access response message.Then, the MAC layer 2 of the mobile station apparatus 1-1 notifies theRRC layer of the mobile station apparatus 1-1 that the random accessprocedure is completed.

In a case where it is notified by the MAC layer 2 of the mobile stationapparatus 1-1 that the random access procedure is completed, the RRClayer of the mobile station apparatus 1-1 creates a message indicatingthat the random access procedure with respect to the base stationapparatus 3-2 is completed, and provides a notification to the PDCPlayer 1 of the mobile station apparatus 1-1 in order to transmit thecreated message to the base station apparatus 3-1. The created messageis processed in the PDCP layer 1 of the mobile station apparatus 1-1,the RLC layer 1 of the mobile station apparatus 1-1, the MAC layer 1 ofthe mobile station apparatus 1-1, and the PHY layer 1 of the mobilestation apparatus 1-1, and is transmitted to the base station apparatus3-1.

In a case where the preamble number is not included in the random accessresponse message, the MAC layer 2 of the mobile station apparatus 1-1again performs random access preamble transmission processing using thepreamble number and the random access channel number, which are notifiedby the RRC layer of the mobile station apparatus 1-1. Furthermore, in acase where the random access response message is not received within afixed period of time after the random access preamble is transmitted,the MAC layer 2 of the mobile station apparatus 1-1 performs the randomaccess preamble transmission processing in the same manner.

Then, in a case where retransmission of the random access preamble isiterated and where the number of times that the random access preambleis transmitted reaches the maximum number of times that the randomaccess is transmitted, which is indicated with the random accessprocedure information, the MAC layer 2 of the mobile station apparatus1-1 determines that the random access procedure fails and notifies theRRC layer of the mobile station apparatus 1-1 of the random accessfailure (the problem with the random access).

Furthermore, the MAC layer 2 of the mobile station apparatus 1-1performs stopping (prohibition) of the uplink transmission to the basestation apparatus 3-2 by the mobile station apparatus 1-1. Specifically,in a case where various timers (for example, the timer associated withthe Buffer Status Report, the timer associated with the Power HeadroomReport, and the transmission timing timer) that are managed in the MAClayer 2 operate, the MAC layer 2 of the mobile station apparatus 1-1stops a timer that operates.

The MAC layer 2 of the mobile station apparatus 1-1 cancels thetriggering (for example, the triggering associated with the BufferStatus Report or the triggering with the Power Headroom Report) that ismanaged in the MAC layer 2. Furthermore, the MAC layer 2 of the mobilestation apparatus 1-1 flushes data in an uplink transmission HARQ bufferthat is managed by the MAC layer 2 of the mobile station apparatus 1-1.The MAC layer 2 of the mobile station apparatus 1-1 deletes the preamblenumber and the random access channel number, which are notified by theRRC layer of the mobile station apparatus 1-1. Moreover, the MAC layer 2of the mobile station apparatus 1-1 may perform the processing describedabove after an instruction from the RRC layer, which indicates thestopping of the uplink transmission processing, is provided.

In a case where the random access failure is notified by the MAC layer 2of the mobile station apparatus 1-1, the RRC layer of the mobile stationapparatus 1-1 creates a message indicating the random access failure(the problem with the random access or a radio link failure) withrespect to the base station apparatus 3-2, and provides the PDCP layer 1of the mobile station apparatus 1-1 with a notification, as datadestined for the base station apparatus 3-1 in order to transmit thecreated message. The created message is processed in the PDCP layer 1 ofthe mobile station apparatus 1-1, the RLC layer 1 of the mobile stationapparatus 1-1, the MAC layer 1 of the mobile station apparatus 1-1, andthe PHY layer 1 of the mobile station apparatus 1-1, and is transmittedto the base station apparatus 3-1.

Furthermore, the RRC layer of the mobile station apparatus 1-1 mayinstruct the PDCP layer 1 of the mobile station apparatus 1-1, and theRLC layer 2 and the MAC layer 2 of the mobile station apparatus 1-1 tochange a radio bearer that corresponds to the base station apparatus 3-2to a radio bearer that corresponds to the base station apparatus 3-1.Moreover, for a radio bearer for which the Bearer Split is configured,the RRC layer of the mobile station apparatus 1-1 may provide aninstruction to release (destroy) a radio bearer that corresponds to thebase station apparatus 3-2. Furthermore, the RRC layer of the mobilestation apparatus 1-1 may configure the radio bearer that is configuredonly for the base station apparatus 3-2, as the radio bearer for thebase station apparatus 3-1. Furthermore, the RRC layer of the mobilestation apparatus 1-1 may be set to provide an instruction to release(destroy) all radio bearers that correspond to the base stationapparatus 3-2.

Furthermore, in order to preclude the uplink transmission to the basestation apparatus 3-2, the RRC layer of the mobile station apparatus 1-1may instruct the PDCP layer 1 of the mobile station apparatus 1-1 todestroy or reestablish data for the base station apparatus 3-2. The RRClayer of the mobile station apparatus 1-1 may instruct the RLC layer 2of the mobile station apparatus 1-1 to perform the re-establishment.Furthermore, the RRC layer of the mobile station apparatus 1-1 maynotify the MAC layer 2 of the mobile station apparatus 1-1 of reset ofthe MAC layer.

Moreover, in re-establishment of the PDCP layer, the PDCP layer performsinitialization processing and the like of the PDCP layer. Inre-establishment of the RLC layer, the RLC layer performs processing,such as destroying data whose processing is not completed in the RLClayer, stopping or resetting the timer associated with the RLC layer, orinitializing or resetting various parameter.

In the reset of the MAC layer, the MAC layer performs processing, suchas initializing each parameter. Specifically, the MAC layer performsprocessing, such as stopping various timers (for example, the timerassociated with the Buffer Status Report, the timer associated with thePower Headroom Report, and the transmission timing timer) that aremanaged in the MAC layer, cancelling the triggering (for example, thetriggering associated with the Buffer Status Report and the triggeringassociated with the Power Headroom Report) that is managed in the MAClayer, flushing data in a downlink reception buffer and an uplinktransmission buffer that are managed by the MAC layer of the mobilestation apparatus 1-1, deleting the preamble number and the randomaccess channel number, stopping the random access procedure, and soforth.

Furthermore, in order not to execute the random access procedure for thebase station apparatus 3-2, the RRC layer of the mobile stationapparatus 1-1 may destroy the physical random access configurationinformation and the random access procedure configuration information,which are associated with the cell of the base station apparatus 3-2. Inthis manner, the mobile station apparatus 1-1 is set not to perform alluplink transmissions to the base station apparatus 3-2. This is alsotrue for a case where the mobile station apparatus 1-1 executes theContention based Random Access Procedure on the base station apparatus3-2.

Moreover, in a case where the mobile station apparatus 1-1 executes therandom access procedure on the base station apparatus 3-1 and where theMAC layer 1 of the mobile station apparatus 1-1 detects the randomaccess failure, the MAC layer 1 of the mobile station apparatus 1-1notifies the RRC layer of the mobile station apparatus 1-1 of the randomaccess failure. In a case where the random access failure is notified bythe MAC layer 1 of the mobile station apparatus 1-1, the RRC layer ofthe mobile station apparatus 1-1 performs an RRC re-establishmentprocedure. Moreover, the RRC re-establishment procedure is a procedurein which communication between the base station apparatus 3-1 and thebase station apparatus 3-2 is discontinued, the selection of the (thebase station apparatus) is made, and the processing that makes theconnection to the selected base station apparatus is performed.

Moreover, when receiving a message indicating the radio link failure(the random access failure) in the base station apparatus 3-2, the basestation apparatus 3-1 transmits a dual connectivity release messageindicating the stopping of the Dual Connect to the mobile stationapparatus 1-1, to the base station apparatus 3-2. In a case where thedual connectivity release message is received, the base stationapparatus 3-2 transfers data of the mobile station apparatus 1-1, whichis present in the base station apparatus 3-2, to the base stationapparatus 3-1. After the data transfer, the base station apparatus 3-2transmits a dual connectivity release response message to the basestation apparatus 3-1. Furthermore, the base station apparatus 3-2destroys information relating to the mobile station apparatus 1-1.

The base station apparatus 3-1 transmits a dual connectivity releasemessage (or an RRC reconfiguration message) indicating release of a cell(cell group) (deletion of a cell) of the base station apparatus 3-2, tothe mobile station apparatus 1-1. When receiving the dual connectivityrelease message (the RRC reconfiguration message) indicating the releaseof the cell (cell group) (the deletion of the cell) of the base stationapparatus 3-2, the mobile station apparatus 1-1 destroys the radioresource configuration information on the cell (the cell group) of thebase station apparatus 3-2.

Furthermore, even in a case where quality abnormality is detected in adownlink wireless channel between the base station apparatus 3-2 and themobile station apparatus 1-1, the mobile station apparatus 1-1 that usesthe Dual Connect may be set to perform the same processing as in thecase of the random access failure.

More precisely, in the radio link between the base station apparatus 3-2and the mobile station apparatus 1-1, in a case where the RRC layer ofthe mobile station apparatus 1-1 detects the radio link failure based oninformation from the PHY layer 2 of the mobile station apparatus 1-1,the RRC layer of the mobile station apparatus 1-1 instructs the PDCPlayer 1 of the mobile station apparatus 1-1, and the RLC layer 2 and theMAC layer 2 of the mobile station apparatus 1-1 to change the radiobearer that corresponds to the base station apparatus 3-2 to the radiobearer that corresponds to the base station apparatus 3-1.

Furthermore, the RRC layer of the mobile station apparatus 1-1 instructsthe PDCP layer 1 of the mobile station apparatus 1-1 to destroy orre-establish the data for the base station apparatus 3-2. The RRC layerof the mobile station apparatus 1-1 notifies the MAC layer 2 of themobile station apparatus 1-1 of the reset of the MAC layer. The RRClayer of the mobile station apparatus 1-1 instructs the RLC layer 2 ofthe mobile station apparatus 1-1 to perform the re-establishment. TheRRC layer of the mobile station apparatus 1-1 may destroy the physicalrandom access configuration information and the random access procedureconfiguration information, which are associated with the cell of thebase station apparatus 3-2.

Moreover, this is also true for the operation of the mobile stationapparatus 1-1 in the case of the Dual Connect as illustrated in FIG. 12.More precisely, in a case where the random access failure is notified bythe MAC layer 4 of the mobile station apparatus 1-1, the RRC layer ofthe mobile station apparatus 1-1 instructs the PDCP layer 4, the RLClayer 4, and the MAC layer 4 of the mobile station apparatus 1-1 tochange the radio bearer that corresponds to the base station apparatus3-2 to the radio bearer that corresponds to the base station apparatus3-1.

Furthermore, the RRC layer of the mobile station apparatus 1-1 instructsthe PDCP layer 4 of the mobile station apparatus 1-1 to destroy orre-establish the data for the base station apparatus 3-2. The RRC layerof the mobile station apparatus 1-1 instructs the RLC layer 4 of themobile station apparatus 1-1 to perform the re-establishment. The RRClayer of the mobile station apparatus 1-1 notifies the MAC layer 4 ofthe mobile station apparatus 1-1 of the reset of the MAC layer.

By doing this, the mobile station apparatus 1-1 can perform the uplinkdata transmission on a suitable cell (or base station apparatus).Furthermore, the base station apparatus 3-1 and the base stationapparatus 3-2 can cause the mobile station apparatus 1-1 to performuplink data transmission control for a suitable cell (or base stationapparatus).

The embodiments of the invention are described in detail above referringto the drawings, but specific constitutions are not limited to thosedescribed above and it is possible that various design amendments andthe like are made within a scope that does not depart from the gist ofthe present invention.

Furthermore, according to the embodiment, the mobile station apparatusis described as one example of a terminal device or a communicationdevice, but it goes without saying that the invention in the presentapplication is not limited to this, and can be applied also to aterminal device or a communication device in a fixed-type electronicapparatus that is installed indoors or outdoors, or a stationary-typeelectronic apparatus, for example, an AV apparatus, a kitchen apparatus,a cleaning or washing machine, an air conditioner, office equipment, avending machine, and other household apparatuses.

Furthermore, for convenience of description, the mobile stationapparatus 1-1, the base station apparatus 3-1 and the base stationapparatus 3-2 according to the embodiment are described referring to thefunctional block diagrams, but a program for realizing a function ofeach unit of the mobile station apparatus 1-1, the base stationapparatus 3-1, and the base station apparatus 3-2, or some of thesefunctions may be recorded on a computer-readable recording medium, acomputer system may be caused to read and run the program recorded onthe recording medium, and thus control of the mobile station apparatusor the base station apparatus may be performed. Moreover, the “computersystem” here is defined as including an OS and hardware components suchas a peripheral device.

Furthermore, the “computer-readable recording medium” refers to aportable medium, such as a flexible disk, a magneto-optical disk, a ROM,and a CD-ROM, and a storage device, such as a hard disk, that is builtinto the computer system. Moreover, the “computer-readable recordingmedia” is defined as including a medium that dynamically retains theprogram for a short period of time, such as a communication line that isavailable when transmitting the program over a network such as theInternet or over a communication line such as a telephone line, and amedium that retains the program for a fixed period of time, such as avolatile memory within the computer system, which functions as a serveror a client in a case where the program is retained dynamically for ashort period of time. Furthermore, the program described above may beone for realizing some of the functions described above and additionallymay be one that can realize the functions described above in combinationwith a program that is already recorded in the computer system.

Furthermore, each functional block that is used according to eachembodiment described above may be realized as an LSI, which is typicallyan integrated circuit. Each functional block may be individually builtinto a chip, and some or all functional blocks may be integrated into achip. Furthermore, a technique for the integrated circuit is not limitedto the LSI, and an integrated circuit for the functional block may berealized as a dedicated circuit or a general-purpose processor.Furthermore, if with advances in semiconductor technology, a circuitintegration technology for a circuit with which an LSI is replaced willappear, it is possible that an integrated circuit to which such atechnology is applied is also used.

The embodiment of the present invention is described above in detailreferring to the drawings, but the specific constitutions are notlimited to the embodiment and a design and the like within a scope thatdoes not depart from the gist of the present invention fall within thescope of claims as well.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a mobile phone, a personalcomputer, a tablet-type computer, and the like.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1-1 to 1-3 MOBILE STATION APPARATUS    -   3-1 BASE STATION APPARATUS IN MACRO CELL    -   3-2 BASE STATION APPARATUS IN SMALL CELL    -   101, 221 UPLINK DATA PROCESSING UNIT    -   121, 201 DOWNLINK DATA PROCESSING UNIT    -   103-1, 103-2, 219, 317 UPLINK CONTROL UNIT    -   105-1, 105-2, 205, 303 TRANSMISSION DATA STORAGE UNIT    -   107-1, 107-2, 207, 305 TRANSMISSION HARQ PROCESSING UNIT    -   109-1, 109-2, 209, 307 TRANSMISSION PROCESSING UNIT    -   111-1, 111-2, 211, 309 WIRELESS UNIT    -   113-1, 113-2, 213, 311 RECEPTION PROCESSING UNIT    -   115-1, 115-2, 215, 313 RECEPTION HARQ PROCESSING UNIT    -   117-1, 117-2, 217, 315 MAC INFORMATION EXTRACTION UNIT    -   119-1, 119-2, 203, 301 DOWNLINK CONTROL UNIT    -   123-1, 123-2, 223, 319 PHY CONTROL UNIT    -   125-1, 125-2, 225, 321 MAC CONTROL UNIT    -   127, 227, 323 RRC CONTROL UNIT    -   229, 325 INTER-BASE STATION APPARATUS COMMUNICATION UNIT    -   231, 327 MME COMMUNICATION UNIT    -   233 GW COMMUNICATION UNIT

The invention claimed is:
 1. A terminal apparatus comprising: a controlcircuit configured or programmed to, in a dual connectivity state wherethe terminal apparatus is configured to communicate simultaneously witha first base station apparatus and a second base station apparatusdifferent from the first base stations apparatus, the first base stationapparatus serving a plurality of cells of a master cell group, and thesecond base station apparatus serving a plurality of cells of asecondary cell group different from the master cell group, upon a randomaccess problem on the secondary cell group being indicated to a radioresource control (RRC) layer of the terminal apparatus from a mediumaccess control (MAC) layer of the terminal apparatus corresponding tothe secondary cell group, suspend a data radio bearer corresponding tothe secondary cell group, suspend an uplink transmission for a splitdata radio bearer corresponding to the secondary cell group, and resetthe MAC layer; and a transmission circuit configured or programmed to,in the dual connectivity state, upon the random access problem beingindicated to the RRC layer from the MAC layer, transmit via the mastercell group, a message indicating a detection of the random accessproblem on the secondary cell group.
 2. A method for a terminalapparatus comprising: in a dual connectivity state where the terminalapparatus is configured to communicate simultaneously with a first basestation apparatus and a second base station apparatus different from thefirst base station apparatus, the first base station apparatus serving aplurality of cells of a master cell group, and the second base stationapparatus serving a plurality of cells of a secondary cell groupdifferent from the master cell group, upon a random access problem onthe secondary cell group being indicated to a radio resource control(RRC) layer of the terminal apparatus from a medium access control (MAC)layer of the terminal apparatus corresponding to the secondary cellgroup, suspending a data radio bearer corresponding to the secondarycell group, suspending an uplink transmission for a split data radiobearer corresponding to the secondary cell group, resetting the MAClayer, and transmitting via the master cell group, a message indicatinga detection of the random access problem on the secondary cell group. 3.An integrated circuit mountable on a terminal apparatus, the integratedcircuit causing the terminal apparatus to perform at least functions of:in a dual connectivity state where the terminal apparatus is configuredto communicate simultaneously with a first base station apparatus and asecond base station apparatus different from the first base stationapparatus, the first base station apparatus serving a plurality of cellsof a master cell group, and the second base station apparatus serving aplurality of cells of a secondary cell group different from the mastercell group, upon a random access problem on the secondary cell groupbeing indicated to a radio resource control (RRC) layer of the terminalapparatus from a medium access control (MAC) layer of the terminalapparatus corresponding to the secondary cell group, suspending a dataradio bearer corresponding to the secondary cell group, suspending anuplink transmission for a split data radio bearer corresponding to thesecondary cell group, resetting the MAC layer, and transmitting via themaster cell group, a message indicating a detection of the random accessproblem on the secondary cell group.